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CHAPTER 4

VALIDITY

In selecting or constructing an evaluation instrument the most important question is: To

what extent will the results serve the particular uses for which they are intene! This isthe essence of valiity"

#any aspects of pupil $ehavior are evaluate in the school% an the results are expecte toserve a variety of uses" &or example% achievement may $e evaluate in orer to iagnoselearning ifficulties or to etermine progress towar instructional o$'ectives( scholasticaptitue may $e measure in orer to preict success in future learning activities or to group

pupils for instructional purposes( an appraisals of personal)social evelopment may $eo$taine in orer to $etter unerstan pupils or to screen them for referral to a guiancecounselor" *egarless of the area of $ehavior $eing evaluate% however% or the use to $emae of the results% all of the various proceures use in an evaluation program shoul

possess certain common characteristics" The most essential of these characteristics can $eclassifie uner the heaings of validity, reliability, an usability.

Valiity refers to the extent to which the results of an evaluation proceure serve theparticular uses for which they are intene" If the results are to $e use to escri$e pupilachievement% we shoul li+e them to represent the specific achievement we wish toescri$e% to represent all aspects of the achievement we wish to escri$e% an to representnothing else" ,ur esires in this regar are similar to the efense attorney in the courtroomwho wants the truth% the whole truth% an nothing $ut the truth" If the results are to $e useto preict pupil success in some future activity% we shoul li+e them to provie as accuratean estimate of future success as possi$le" -asically% then% valiity is always concerne withthe specific uset.$e mae of evaluation results an with the sounness of our proposeinterpretations"

*elia$ility refers to the consistency of evaluation results" If we o$tain quite similarscores when the same test is aministere to the same group on two ifferent occasions% wecan conclue that our results have a high egree of relia$ility from one occasion to another"/imilarly% if ifferent teachers inepenently rate the same pupils on the same instrumentan o$tain similar ratings% we can conclue that the results have a high egree of relia$ilityfrom one rater to another" As with valiity% relia$ility is intimately relate to the type ofinterpretation to $e mae" &or some uses% we may $e intereste in as+ing how relia$le ourevaluation results are over a given perio of time% an for others% how relia$le they are oversamples of the same $ehavior" In all instances in which relia$ility is $eing etermine%however% we are concerne with the consistency of the results% rather than with the extent towhich they serve the specific use uner consieration"

Although relia$ility is a highly esire quality% it shoul $e note that relia$ility provies

no assurance that evaluation results will yiel the esire information" As with a witnesstestifying in a courtroom trial0the fact that he consistently tells the same story oes notguarantee that he is telling the truth" The truthfulness of his statements can $e etermineonly $y comparing them with some other evience" /imilarly% with evaluation resultsconsistency is an important quality $ut only if it is accompanie $y evience of valiity% anthat must $e etermine inepenently" Little is accomplishe if evaluation resultsconsistently provie the wrong information" In short% relia$ility is a necessary $ut not asufficient conition for valiity"

In aition to proviing results which possess a satisfactory egree of valiity anrelia$ility% an evaluation proceure must meet certain practical requirements" It shoul $eeconomical from the viewpoint of $oth time an money% it shoul $e easily aministerean score% an it shoul provie results that can $e accurately interprete an applie $ythe school personnel availa$le" These practical aspects of an evaluation proceure can all $e

inclue uner the heaing of usa$ility" The term usability, then% refers only to thepracticality of the proceure an implies nothing a$out the other qualities present"

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In this chapter we shall consier the valiity of evaluation results% an in the followingchapter we shall turn our attention to relia$ility an usa$ility"

1AT2*3 ,& VALIDITY

hen using the term validity, in relation to testing an evaluation% there are a num$er ofcautions to $e $orne in min"

5" Valiity pertains to the results of a test% or evaluation instrument% an not to theinstrument itself" e sometimes spea+ of the valiity of a test for the sa+e ofconvenience% $ut it is more appropriate to spea+ of the valiity of the test results% or morespecifically% of the valiity of the interpretation to $e mae from the results"

6" Valiity is a matter of degree. It oes not exist on an all)or)none $asis" 7onsequently% weshoul avoi thin+ing of evaluation results as vali or invali" Valiity is $est consierein terms of categories that specify egree% such as high valiity% moerate valiity% anlow valiity"

8" Valiity is alwaysspecific to some particular use. It shoul never $e consiere a generalquality" &or example% the results of an arithmetic test may have a high egree of valiityfor inicating computational s+ill% a low egree of valiity for inicating arithmeticalreasoning% a moerate egree of valiity for preicting success in future mathematicscourses% an no valiity for preicting success in art or music" Thus% when appraising orescri$ing valiity% it is necessary to consier the use to $e mae of the results"3valuation results are never 'ust vali( they have a ifferent egree of valiity for each

particular interpretation to $e mae"

TY93/ ,& VALIDITY

Three $asic types of valiity have $een ientifie an are now commonly use ineucational an psychological measurement"5They are: content valiity% criterion-related

valiity% an construct valiity" The general meaning of these types of valiity is inicatein Ta$le 4"5" 3ach type will $e explaine more fully as the chapter procees" &or the sa+e ofclarity% the iscussion will $e limite to valiity as it relates to testing proceures" It shoul

$e recognie% however% that these three types of valiity are also applica$le to all of thevarious +ins of evaluation instruments use in the school"

7ontent Valiity

The content of a course or curriculum may $e $roaly efine to inclue $oth su$'ect)matter content an instructional o$'ectives" The former is concerne with the topics% orsu$'ect)matter areas% to $e covere% an the latter with the $ehavioral changes sought in

pupils" -oth of these aspects of content are of concern in etermining content valiity" eshoul li+e any achievement test we construct% or select% to provie results which arerepresentative of the topics an $ehaviors we wish to measure" This is the essence ofcontent valiity" #ore formally% content validity may be defined as the extent to which a testmeasures a representative sample of the subject-metter content and the behavioral changesunder consideration.

TA-L3 4"5

T;*33 TY93/ ,& VALIDITY

TY93 #3A1I1< 9*,73D2*3

7ontent Valiity

7*IT3*I,1)*3LAT3D

VALIDITY

;ow well the test measuresthe su$'ect)matter contentan $ehaviors unerconsieration

;ow well test performancepreicts future performanceor estimates current

performance on some valuemeasure other than the testit lf

7ompare test content to theuniverse of content an

$ehaviors to $e measure

7ompare test scores with an)

other measure of performanceo$taine at a later ate =for

preiction> or with anotherf f

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7,1/T*27TVALIDITY

;ow test performance can

$e escri$e psychologically

estimating present status>

3xperimentally etermine whatfactors influence scores on thetest

The focus of content validity, then, is on the adequacy of the sampleand not simply on the appearance of the test. A test that appears to be arelevant measure, based on supercial examination, is said to have facevalidity. Althouh a test should loo! li!e an appropriate measure toobtain the cooperation of those ta!in the test, face validity should notbe considered a substitute for content validity.

As miht be expected, content validity is of primary concern inachievement testin. The procedures used are those of loical analysisand comparison. The test is examined to determine the sub"ect#mattercontent covered and the responses pupils are intended to ma!e to thecontent, and this is compared $ith the domain of achievement to bemeasured. Althouh this is sometimes done in a rather hapha%ardmanner, reater assurance of content validity is obtained by&observinthe follo$in steps'

1. The ma"or topics of sub"ect#metter content and the ma"or type ofthe behavioral chanes to be measured by the test are separatelylisted. This list are usually derived from the topical content and theob"ectives emphasi%ed in the instructional proram. (f the test is tomeasure achievement in a specic course, the teacher involvedmiht develop the list. (f the test is to be used on a school#$idebasis, the preparation of the list miht best be handled by acommittee a of teachers.

). The various sub"ect#matter topic and types of behavioral chanesare $eihted in term of their relative importance. There is nosimple procedure for determinin appropriate relative $eiht forthe various topic and behaviors. (t depends on personal "udementas uided by the amount of time devoted to each area durininstruction, the philosophy on the school. The opinion of experts inthe area, and similar criteria.

3. A ta$le of specifications% li+e the one presente in 7hapter 8% is $uilt from theweighte lists of su$'ect)matter topics an expecte $ehavioral changes" This ta$le%then% specifies the relative emphasis the test shoul give to each su$'ect)matter topican each type of $ehavioral change"

*. The achievement test is constructe% or selecte% in accorance with the ta$le ofspecifications" The closer the test correspons to the specifications inicate in theta$le% the greater the li+elihoo that the pupils? responses to the test will have a highegree of content valiity"

A ta$le of specifications% in a very simple form% is presente in Ta$le 4"6 to illustrate howsuch a ta$le is use to chec+ on content valiity" The percentages in the ta$le inicate therelative egree of emphasis each su$'ect)matter area an each type of $ehavioral change isto $e given in the test" Thus% if the test is to measure a representative sample of subject-matter content, 5@ per cent of the test items shoul $e concerne with plants% 5@ per centwith animals% 8. per cent with weather% 5@ per cent

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/+y 5. 5@ 6@

Total @. @. 5..

with the earth% an 6@ per cent with the s+y" If the test is to measure a representative sampleof behavioral changes, @. per cent of the items shoul measure the Bunerstaning ofconcepts%B an @. per cent shoul measure the Bapplication of concepts"B This% of course%implies that the specific emphasis on BunerstaningB an BapplicationB for each su$'ect)matter area will follow that inicate $y the percentages in the ta$le of specifications" &orexample% 5. per cent of the test items concerne with plants shoul measure Bunerstaningof concepts%B an @ per cent of the test items shoul measure Bapplication of concepts"B

It shoul $e note that this proceure merely provies a rough chec+ on contentvaliity" /uch an analysis reveals the apparent relevance of the test items to the su$'ect)matter areas an $ehavioral changes to $e measure" 7ontent valiity is concerne with theextent to which the test items actually o call forth the responses represente in the ta$le ofspecifications" Test items may appear to measure BunerstaningB $ut not function asintene $ecause of efects in the items% unclear irections% inappropriate voca$ulary% or

poorly controlle testing conitions" Thus% content valiity is epenent on a host of factorsother than the apparent relevance of the test items" #ost of what is written in this $oo+concerning the construction an selection of achievement tests is irecte towar improvingthe content valiity of the o$taine results"

Although our iscussion of content valiity has $een limite to achievement testing%

content valiity is also of some concern in" the measurement of aptitues% interests%attitues% an personal)social a'ustment" &or example% if we are selecting an interestinventory we shoul li+e it to cover those aspects of interest with which we are concerne"/imilarly% an attitue scale shoul inclue those attituinal topics that are in accor with theo$'ectives we wish to measure" The proceure here is essentially the same as that inachievement testing" It is a matter of analying the test materials an the outcomes to $emeasure an 'uging the egree of corresponence $etween them"

7riterion)*elate Valiity

henever test scores are to $e use to preict future performance or to estimate currentperformance on some value measure other than the test itself% we are concerne withcriterion)relate valiity" &or example% reaing reainess test scores might $e use to preict

pupils? future achievement in reaing% or a test of ictionary s+ills might $e use to estimate

pupils? current s+ill in the actual use of the ictionary =as etermine $y o$servation>" In thefirst example% we are intereste inprediction an thus in the relationship $etween the twomeasures over an extene perio of time" This type of valiity is callepredictive valiity"In the secon example% we are intereste in estimating present status an thus in therelationship $etween the two measures o$taine concurrently" A high relationship in thiscase woul show that the test of ictionary s+ills is a goo inicator of actual s+ill in use ofthe ictionary" This proceure for etermining valiity is calle concurrent valiity" In thenew test !tandards,% the esignations of preictive valiity an concurrent valiity have

$een su$sume uner the more general category0criterion-related valiity" This appears to$e a esira$le arrangement $ecause the metho of etermining an expressing valiity is thesame in $oth cases" The ma'or ifference resies in the time perio $etween the twoo$taine measures"

Criterion-related validity may be defined as the extent to which test performance isrelated to some other valued measure of performance. As note earlier% the secon measureof performance may $e o$taine at some future ate =when we are intereste in preictingfuture performance>% or concurrently =when we are intereste in estimating present

performance>" &irst let us examine the use of criterion)relate valiity from the stanpointof preicting success in some future activity" Then we shall return to its secon use"

9reicting &uture 9erformance" /uppose that #r" Young% a 'unior high school teacher%wants to etermine how well scores from a certain scholastic aptitue test preict success inhis seventh)grae arithmetic class" /ince the scholastic aptitue test is aministere to all

pupils when they enter 'unior high school% these scores are reaily availa$le to #r" Young";is $iggest pro$lem is eciing on a criterion of successful achievement in arithmetic" &orlac+ of a $etter criterion% #r" Young ecies to use a comprehensive epartmentalexamination that is aministere to the various seventh)grae arithmetic sections at the enof the school year" It is now possi$le for #r" Young to etermine how well the scholasticaptitue test scores preict success in his arithmetic class $y comparing the pupils?

scholastic aptitue test scores with their scores on the epartmental examination" Do thosepupils who have high scholastic aptitue test scores also ten to have high scores on the

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TA+- *.3

)) / 3)

epartmental examination! Do those who have low scholastic aptitue test scores also tento have low scores on the epartmental examination! If this is the case% #r" Young isincline to agree that the scholastic aptitue test scores ten to $e accurate in preictingachievement in this arithmetic class" In short% he recognies that the test results possesscriterion)relate valiity"

In our illustration% #r" Young merely inspecte the scholastic aptitue test scores an theachievement test scores to etermine the agreement $etween them" Although this may $e aesira$le preliminary step% it is selom sufficient for inicating criterion)relate valiity"The usual proceure is to correlate statistically the two sets of scores an to report theegree of relationship $etween them $y means of a correlation coefficient" This ena$lesvaliity to $e presente in precise an universally unerstoo terms" They are% of course%Buniversally unerstooB only $y those who unerstan an can interpret correlationcoefficients" This shoul pose no great pro$lem% however% since the meaning of correlationcoefficient can $e easily graspe $y persons whose computational s+ill goes no further thanthat of simple arithmetic"

*an+)Difference 7orrelation" To clarify the calculation an interpretation of correlationcoefficients% let?s consier the exact scores #r" Young?s pupils receive on $oth thescholastic aptitue test an the epartmental examination in arithmetic" This information is

provie in the first two columns of Ta$le 4"8" -y inspecting these two columns of scores%as #r" Young i% it is possi$le to note that high scores in 7olumn 5 ten to go with highscores in 7olumn 6" This comparison is ifficult to ma+e% however% since the sies of thetest scores in the two columns are ifferent"

The agreement of the two sets of scores can $e more easily mae if the test scores areconverte to ran+s" This has $een one in 7olumns 8 an 4 of Ta$le 4"8" 1ote that the pupilwho was first on the aptitue test ran+e thir on the arithmetic test( the pupil who wassecon on the aptitue test ran+e fourth on the arithmetic test( the pupil who was thir onthe aptitue test ran+e sixth on the arithmetic test( an so on" 7omparing the ran+ orer ofthe pupils on the two tests% as inicate in 7olumns 8 an 4 of Ta$le 4"8% gives us a fairlygoo picture of the relationship $etween the two sets of scores" &rom this inspection we

+now that pupils who ha a high staning on the aptitue test also ha a high staning onthe arithmetic test% an pupils who ha a low staning on the aptitue test also ha a lowstaning on the arithmetic test" ,ur inspection of 7olumns 8 an 4 also shows us% however%th t th l ti hi $ t th il ? + th t t t i t f t Th i

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the egree of relationship $etween these two sets of ran+s in meaningful terms! This iswhere the correlation coefficient $ecomes useful"

The ran+)ifference correlation is simply a metho of expressing the egree ofrelationship $etween two sets of ran+s" The steps in etermining a ran+)ifferencecorrelation coefficient are presente in the following computing guie" #r" Young?s ata% inTa$le 4"8% are use to illustrate the proceure" It will $e note that the isuse to ientify a ran+)orer correlation coefficient" &rom our computations for #r" Young?sata we fin that PC "." This correlation coefficient is a statistical summary of the egreeof relationship $etween the two sets of scores in #r" Young?s ata" In this particularinstance% it inicates the extent to which the fall aptitue test scores =preictor> are

preictive of the spring arithmetic test scores =criterion>" In short% it refers to the criterion)relate valiity of the aptitue test scores"

COMPUTING GUIDE : RANK - DIFFERENCE CORRELATION

!teps &esults in $able '.5 Arrange pairs of scores% for each pupils% in coloums 7olomns 5 an 66 *an+ pupils from 5 to 1 =1um$er af each set of

scores7olumns 8 an 4

8 &in the ifference =D> in ran+s $y su$tracting the ran+in the right)han colum =7olumn 4> from the ran+s inthe left)han column =7olums 8>

7olumn @

4 /quare each ifference in ran+ =column @> to o$tainifference square =D6>

7olumn

@ /um the square ifferences in 7olumn to o$tain D6 -ottom of 7olumn

Apply the following formula:

=rho> C 5 E =xD6>F1=16)5>C sum ofD C Difference in ran+

1 C 1um$er in group

C 5 E x@86 F 6. =6.6E 5 > C 5) 85G6FHG. C 5 ) "4. C ".

;ow goo is #r" Young?s valiity coefficient of ".! /houl #r" Young $e happy withthis fining or shoul he $e isappointe! Does this particular aptitue test provie a goo

preiction of future performance in arithmetic!2nfortunately% simple an straightforwar answers cannot $e given to such questions"

The interpretation of correlation coefficients is epenent upon information from a varietyof sources" &irst% we +now that the following correlation coefficients inicate the extremeegrees of relationship that it is possi$le to o$tain $etween varia$les:

5%.. C perfect positive relationship

.%.. C no relationship

0 5".. C perfect negative relationship

/ince #r" Young?s valiity coefficient is ".% we +now that the relationship is positive $utsomewhat less than perfect" ,$viously% the nearer a valiity coefficient approaches 5".. thehappier we are with it $ecause larger valiity coefficients inicate greater accuracy in

preicting from one varia$le to another"6

Another way of evaluating #r" Young?s valiity coefficient of ". is to compare it to thevaliity coefficients o$taine with other methos of preicting performance in arithmetic" Ifthis valiity coefficient is larger than those o$taine with other preiction proceures% #r"Young will continue to use the "scholastic aptitue test as the $est means availa$le to him

for preicting the arithmetic performance of his pupils" Thus% valiity coefficients are largeor small only in relation to each other" here criterion)relate valiity is an important

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apted from tables in 2. . Thorndi!e and -. aen, 4easurement and -valuation in 5sycholoy an

consieration% we shall always consier more favora$le the test with the largest valiitycoefficient" In this regar% even aptitue tests with rather low valiity may $e useful% how)ever% if they are the $est preictors availa$le% an the preictions they provie are $etterthan chance"

9ro$a$ly the easiest way of grasping the practical meaning of a correlation coefficient isto note how the accuracy of preiction increases as the correlation coefficient $ecomeslarger" This is shown in the various charts presente in Ta$le 4"4" The rows in each chartrepresent the fourths of a group on some preictor =such as a scholastic aptitue test> anthe columns inicate the percentage of persons falling in each fourth on the criterionmeasure =such as an achievement test>" &irst note that for a correlation coefficient of "..%

$eing in the top quarter on the preictor provies no $asis for preicting where a personmight fall on the criterion measure" ;is chances of falling in each quarter are equally goo"

1ow turn to the chart for a correlation coefficient of "." 1ote% here% that if a person falls inthe top quarter on the preictor% he has @4 chances out of a 5.. of falling in the top quarteron the criterion measure% 6 chances out of 5.. of falling in the secon quarter% 54 chancesout of 5.. of falling in the thir quarter% an only 4 chances out of 5.. of falling in the

$ottom quarter" The remainer of the chart is rea in a similar manner"

-y comparing the charts for the ifferent)sie correlation coefficients% it is possi$le to getsome feel for the meaning of correlation coefficient in terms of preiction efficiency" As thecorrelation coefficient $ecomes larger% a person?s chances of $eing in the same quarter onthe criterion measure as he is on the preictor are increase" This can $e seen $y loo+ing atthe entries in the iagonal cells" ith a correlation coefficient of 5"..% each iagonal cellwoul% of course% contain 5.. per cent of the cases0inicating perfect preiction from onemeasure to another"

3stimating 9resent 9erformance" 2p to this point we have emphasie the role ofcriterion)relate valiity in preicting future performance" Although this is pro$a$ly itsma'or use% there are times when we are intereste in the relation of test performance to someother current measure of performance" In this case% we woul o$tain $oth measures atapproximately the same time an correlate the results" This is commonly one when a test is

$eing consiere as a replacement for a more time)consuming metho of o$taininginformation" &or example% #r" -rown% the $iology teacher% wonere if an o$'ective test ofstuy s+ills coul $e use in place of the ela$orate o$servation an rating proceures he wascurrently using" ;e felt that if a test coul $e su$stitute for the more complex proceures%he woul have much more time to evote to iniviual pupils uring the supervise stuy

perio" An analysis of the specific pupil $ehaviors on which he rate the pupils? stuy s+illsinicate that many of the proceures coul $e state in the form of o$'ective test questions"7onsequently% he evelope an o$'ective test of stuy s+ills that he aministere to his

pupils" To etermine how aequately his test measure stuy s+ills he correlate the testresults with his ratings of the pupils? stuy s+ills" A resulting correlation coefficient of "H@inicate consiera$le agreement $etween the test results an the criterion measure" Thiscorrelation coefficient represents the criterion)relate valiity of #r" -rown?s test of stuys+ills"

e might also correlate test performance with some other current measure ofperformance to etermine if a preictive stuy is worth oing" &or example% if a set ofscholastic aptitue test scores correlate to a sufficiently high egree =e"g"% ".> with a set ofachievement test scores o$taine at the same time it woul inicate that the scholastic

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TA+- *.ectancy table sho$inc the relation bet$een fall aptitude scores and sprin arithmetic scores

Brom data in Biure *.1.

the other han% a low correlation woul iscourage us from carrying out the preictivestuy% $ecause we +now that the correlation woul $ecome still lower when the time perio

$etween measures was extene" ,ther things $eing equal% the larger the time span $etweentwo measures the smaller the correlation coefficient"

3xpectancy Ta$le" ;ow well a test preicts future performance or estimates currentperformance on some criterion measure can also $e shown $y irectly plotting the ata in atwofol chart li+e the one shown in &igure 4"5" ;ere% #r" Young?s ata =from Ta$le 4"8>have $een ta$ulate $y placing a tally showing each iniviual?s staning on $oth the fallaptitue scores an the spring arithmetic scores" &or example% ohn score 55G on the fallaptitue test an HH on the spring arithmetic test% so a tally% representing his performance%was place in the upper right)han cell" The performance of all other pupils on the two testswas tallie in the same manner" Thus% each tally mar+ in &igure 4"5 represents how welleach of #r" Young?s twenty pupils performe on the fall an spring tests" The total num$erof pupils in each cell% an in each column an row% have also $een inicate"

The expectancy gri shown in &igure 4"5 can $e use irectly as an expectancy ta$le%simply $y using the frequencies in each cell" The interpretation of such information issimple an irect" &or example% of those pupils who score a$ove average on the fallaptitue test% none score $elow @ on the spring arithmetic test% 6 out of @ score $etween@ an H4% an 8 out of @ score $etween H@ an 4" ,f those who score $elow average onthe fall aptitue test% none score in the top category on the spring arithmetic test an 4 outof @ score $elow @" These interpretations are limite to the group teste $ut from suchresults one might ma+e preictions concerning future pupils" e can say% for example% that

pupils who score a$ove average on the fall aptitue test will pro$a$ly score a$ove averageon the spring arithmetic test" ,ther preictions can $e mae in the same way $y noting thefrequencies in each cell of the gri in &igure 4"5"

#ore commonly% the figures in an expectancy ta$le are expresse in percentages" This isreaily o$taine from the gri $y converting each cell frequency to a percentage of the totalnum$er of tallies in its row" This has $een one for the ata in &igure 4"5 an the results are

presente in Ta$le 4"@" The first row of the ta$le shows that of the @ pupils who scorea$ove average on the fall aptitue test% 4. per cent =6 pupils> score $etween @ an?H4 onthe spring arithmetic test% an . per cent =8 pupils> score $etween H@ an 4" Theremaining rows are rea in a similar manner" The use of percentage ma+es the figures ineach row an column compara$le" ,ur preictions can then $e mae in stanar terms =thatis% chances out of 5..> for all score levels" ,ur interpretation is apt to $e a little clearerif we say ;enry?s chances of $eing in the top group on the criterion measure are . out of5.. an *alph?s are only 5. out of 5..% than if we say ;enry?s chances are 8 out of @ an

*alph?s are 5 out of 5."

3xpectancy ta$les ta+e many ifferent forms an may $e use to show the relation$etween various types of measures" The num$er of categories use with the preictor% orcriterion% may $e as few as two or as many as seem esira$le" Also% the preictor may $eany set of measures for which we wish to esta$lish criterion)relate valiity an thecriterion may $e course graes% ratings% test scores% or whatever other measure of success isrelevant"

hen interpreting expectancy ta$les $ase on a small num$er of cases% li+e #r" Young?sclass of twenty pupils% our preictions shoul $e regare as highly tentativeB 3ach

percentage is $ase on so few pupils that we can expect large fluctuations in these figures

from one group of pupils to another" It is frequently possi$le to increase the num$er ofpupils represente in the ta$le $y com$ining test results from several classes" here this isone% our percentages are% of course% much more sta$le% an our preictions can $e maewith greater confience In any event expectancy ta$les provie a simple an irect means

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The B7riterionB 9ro$lem" In the etermination of criterion)relate valiity% a ma'orpro$lem is that of o$taining a satisfactory criterion of success" It will $e recalle that #r"Young use a comprehensive epartmental examination as the criterion of success in hisseventh)grae arithmetic class" #r" -rown use his own ratings of the pupils? stuy s+ills" Ineach instance the criterion of success was only partially suita$le as a $asis for testvaliation" #r" Young recognie that the epartmental examination i not measure all ofthe important learning outcomes that he aime at in teaching arithmetic" There was notnearly enough emphasis on arithmetic reasoning( the interpretation of graphs an charts wassaly neglecte( an% of course% the test i not evaluate the pupils? attitues towararithmetic =which #r" Young consiere to $e extremely important>" Li+ewise% #r" -rownwas well aware of the shortcomings of his rating of pupils? stuy s+ills" ;e sense that some

pupils Bput on a showB when they +new they were $eing o$serve" In other instances he feltthat some of the pupils were pro$a$ly overrate on stuy s+ills $ecause of their highachievement in class wor+" Despite these recognie shortcomings% $oth #r" Young an #r"-rown foun it necessary to use these criterion measures $ecause they were the $estcriterion measures availa$le"

The plights of #r" Young an #r" -rown in locating a suita$le criterion of success forthe purpose of test valiation are not unusual" The selection of a satisfactory criterion is oneof the most ifficult pro$lems in valiating a test" &or most eucational purposes% noaequate criterion of success exists" Those which are use ten to $e lac+ing incomprehensiveness an in most cases provie results that are less sta$le than those of thetest $eing valiate"

The lac+ of a suita$le criterion for valiating achievement tests has importantimplications for the classroom teacher" /ince statistical types of valiity will usually not $eavaila$le% teachers will have to epen on proceures of logical analysis to assure testvaliity" This means carefully ientifying the o$'ectives of instruction% stating theseo$'ectives in terms of specific changes in pupil $ehavior% an constructing or selectingevaluation instruments which satisfactorily measure the $ehavioral changes sought in

pupils" Thus% content valiity will assume a role of ma'or importance in the teacher?sevaluation of pupil progress"

Construct Valiit!

The two types of valiity thus far escri$e are $oth concerne with some specificpractical use of test results" They help us etermine how well test scores represent theachievement of certain learning outcomes =content valiity>% or how well they preict orestimate a particular performance =criterion)relate valiity>" In aition to these morespecific an immeiately practical uses% we may wish to interpret test scores in terms ofsome general psychological quality" &or instance% rather than spea+ a$out a pupil?s score ona particular arithmetic test% or how well it preicts success in mathematics% we might wantto infer that the pupil possesses a certain egree of reasoning ability. This provies a $roageneral escription of pupil $ehavior which has implications for many ifferent uses"

henever we wish to interpret test performance in terms of some psychological trait orquality% we are concerne with construct valiity" A construct is a psychological qualitywhich we assume exists in orer to explain some aspect of $ehavior" *easoning a$ility is aconstruct" hen we interpret test scores as measures of reasoning a$ility% we are implyingthat there is a quality that can $e properly calle reasoning a$ility an that it can account tosome egree for performance on the test" Verifying such implications is the tas+ of constructvaliation"

7ommon examples of constructs are intelligence% scientific attitue% critical thin+ing%reaing comprehension% stuy s+ills% an mathematical aptitue" There is an o$viousavantage in $eing a$le to interpret test performance in terms of such psychologicalconstructs" 3ach construct has an unerlying theory which can $e $rought to $ear inescri$ing an preicting a person?s $ehavior" If we say a person is highly intelligent% forexample% we +now what $ehaviors might $e expecte of him in various specific situations"

Construct validity may be defined as the extent to which test performance can beinterpreted in terms of certain psychological constructs. Theprocess of eterminingconstruct valiity involves the following steps: =5> ientifying the constructs presume toaccount for test performance( =6> eriving hypotheses regaring test performance from thetheory unerlying the construct( =8> verifying the hypothesis $y logical an empiricalmeans" &or example% let us suppose that we wish to chec+ the claim that a newlyconstructe test measures intelligence" &rom what is +nown a$out Bintelligence%B we mightma+e the following preictions:

5" The test scores will increase with age =intelligence is assume to increase with age untilapproximately age sixteen>"

6 Th t t ill i t i h l hi t

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4" The test scores will $e positively relate to scores on other so)calle intelligence tests"@" The test scores will iscriminate $etween groups which are +nown to iffer% such as

BgifteB an Bmentally hanicappe"B" The test scores will $e little influence $y irect teaching"

3ach of these preictions% an others% woul then $e teste% one $y one" If positive resultsare o$taine for each preiction% the com$ine evience lens support to the claim that thetest measures intelligence" If a preiction is not confirme% say the scores o not increasewith age% we must conclue that either the test is not a vali measure of intelligence% orthere is something wrong with our theory" As 7ron$ach an #eehl8 have inicate% withconstruct valiation $oth the theory an the test are $eing valiate at the same time"

#ethos 2se in ,$taining 3vience for 7onstruct Valiation" As note in ourillustration% there is no aequate single metho of esta$lishing construct valiity" It is amatter of accumulating evience from many ifferent sources" e may use $oth contentvaliity an criterion)relate valiity as partial evience to support construct valiity% $utneither of them alone is sufficient" 7onstruct valiation epens on logical inferences rawnfrom a variety of types of ata" The following proceures illustrate the $roa range ofmethos that might $e use in o$taining evience for construct valiity:

5""nalysis of the mental process re)uired by the test items. ,ne may analye the mentalprocesses involve $y examining the test items to etermine what factors they appear tomeasure anFor $y aministering the test to iniviual pupils an having them Bthin+ alouB

as they answer" Thus% examination of a science test may inicate that the test scores areli+ely to $e influence $y +nowlege% comprehension% an quantitative a$ility" /imilarly%Bthin+ing alouB on an arithmetic reasoning test may verify that the items call for theintene reasoning process% or it may reveal that most pro$lems can $e solve $y a simpletrial)an)error proceure"

6" Comparison of the scores of *nown groups. In some cases% it is possi$le to preictthat scores will iffer from one group to another" These may $e age groups% $oys angirls% traine an untraine% a'uste an mala'uste% an the li+e" &or example%most a$ilities increase with age =at least uring chilhoo an aolescence>% an

$oys o$tain higher scores than girls on certain tests =e"g"% mechanicalcomprehension>" Also% it is reasona$le to expect that achievement test scores will

iscriminate $etween groups with ifferent amounts of training an that scores ona'ustment inventories will iscriminate $etween groups of a'uste anmala'uste iniviuals" Thus% a preiction of ifferences for a particular test can $echec+e against groups that are +nown to iffer an the results use as partialsupport for construct valiation"

8" Comparison of scores before and after some particular treatment. /ome test scorescan $e expecte to $e fairly resistant to specific training =e"g"% intelligence>% whereasothers can $e expecte to increase =e"g"% achievement>" /imilarly% some test scorescan $e expecte to change as certain types of experimental treatment are introuce"&or example% we woul expect the scores on an anxiety test to change wheniniviuals are su$'ecte to an anxiety)proucing experience" Thus% from the theoryunerlying the trait $eing measure% we can ma+e preictions that the scores of a

particular test will change =or remain sta$le> uner various conitions" If our

preictions are verifie% the results provie further support for construct valiation"

4" Correlations with other tests. The scores of any particular test can $e expecte tocorrelate su$stantially with the scores of other tests that presuma$ly measure thesame thing" -y the same to+en% the test scores can $e expecte to have lowercorrelations with tests that were esigne to measure a ifferent a$ility or trait" &orexample% we woul expect a set of scholastic aptitue test scores to correlate ratherhighly with those of another scholastic aptitue test% $ut much lower with the scoresof a musical aptitue test" Thus% for any given test% we woul preict highercorrelations with li+e tests an lower correlations with unli+e tests" In aition% wemight also preict that the test scores woul correlate with various practical criteria"/cholastic aptitue scores% for example% shoul correlate satisfactorily with school

graes% achievement test scores% an other measures of achievement" This latter typeof evience is% of course% criterion)relate valiity" ,ur interest here% however% is not

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in the immeiate pro$lem of preiction% $ut rather in using these correlations tosupport the claim that the test is a measure of scholastic aptitue" As inicateearlier% construct valiation epens on a wie array of evience% incluing that

provie $y the other types of valiity"

In examining construct valiity% our interest is not limite to the psychological construct thetest was esigne to measure" Any factor which might influence the test scores is oflegitimate concern" &or example% although a test author claims his test measures arithmeticreasoning% we might rightfully as+ to what extent the test scores are influence $ycomputational s+ill% reaing a$ility% an similar factors" -roaly conceive% constructvaliity is an attempt to account for the ifferences in test scores" Instea of as+ing% BDoesthis test measure what the author claims it measures!B we are as+ing% B9recisely what oesthis test measure! ;ow can we most meaningfully interpret the scores in psychologicalterms!B The aim of construct valiation is to ientify the nature an strength of all factorsinfluencing performance on the test"

7onstruct valiity is of importance in all types of testing0achievement% aptitue% anpersonal)social evelopment" hen selecting any stanarie test% we shoul note whatinterpretations are suggeste for the test an then review the test manual to etermine thetotal availa$le evience supporting these interpretations" The confience with which we canma+e the propose interpretations is irectly epenent on the type of evience presente"Also% if we suspect that test scores are influence $y factors other than those escri$e in

the manual =such as spee an reaing a$ility>% we shoul chec+ these hunches with asuita$le experiment of our own"

VALIDIT" OF CRITERION-REFERENCED MA#TER"TE#T#

As note in 7hapter 5% norm)reference tests are esigne to emphasie ifferences amonginiviuals" An iniviual?s performance on a norm)reference test has little meaning $yitself" To $e meaningful% the test performance must $e compare to the performance ofothers who have ta+en the test" e 'uge whether a norm)reference score is high or low $y?noting its relative position in a set of scores" -asic to this measurement approach is a wiesprea of test scores so that epena$le iscriminations can $e mae among iniviuals" ecan spea+ of ifferences $etween Tom an -ill an #ary an ane with greater confienceif the score ifferences are large" This varia$ility among scores% that is essential to norm)reference testing% is also necessary for computing valiity coefficients" In fact% most of thetraitional statistical measures for estimating valiity an relia$ility use formulas $ase onthe varia$ility among scores" Thus% although all of the various estimates of valiityiscusse earlier are appropriate for norm)reference testing% they are not completelyappropriate for 'uging the valiity of criterion)reference mastery tests"

hereas varia$ility among scores is essential for norm)reference tests% it is irrelevant forcriterion)reference mastery tests" These tests are esigne to escri$e the types of tas+s aniniviual can perform" If all pupils can perform a given set of tas+s =e"g"% ientify themeasuring instruments inclue in a weather unit> at the en of instruction% an thus all get

perfect scores =ero varia$ility>% so much the $etter" &rom a mastery learning stanpoint%$oth the test an the instruction woul appear to $e effective" /ince varia$ility among scoresis not a necessary conition for a goo criterion)reference mastery test% the conventionalstatistical measures for etermining valiity are inappropriate"

The type of valiity that is of greatest importance for criterion)reference mastery tests iscontent valiity" The proceures for o$taining content valiity escri$e earlier in thischapter are as applica$le here as they are with norm)reference tests" The fact that criterion)reference mastery tests are typically confine to a more elimite omain of learning tas+s=e"g"% unit or chapter>% even simplifies the process of efining an selecting a representativesample of tas+s" In some cases% the omain of tas+s is so limite =e"g"% aition of single)igit whole num$ers> that a representative sample can $e o$taine without the use of a ta$leof specifications"

Although content valiity is of primary concern with criterion)reference mastery tests%we might also $e intereste in using the test results to ma+e preictions a$out pupils" emight% for example% use a criterion)reference pretest to preict which pupils are li+ely to

master the material in a unit of instruction% or use an en)of)unit mastery test to eterminewhich pupils shoul procee to the next unit of instruction" /uch instructional ecisionsrequire some evience =criterion)relate valiity> that our ecisions are sounly $ase" Thisevience can $e o$taine $y means of an expectancy ta$le li+e the one shown in Ta$le 4

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TA+- *.C

pectancy table sho$inc the relation bet$een pretest scores and the number of students attainin

67 / 30?&

om 7. -. Dronlund, 5reparin Eriterion#2eferenced Tests for Elassroom (nstruction. 7e$ 8or!' 4acm

faile to achieve mastery at the en of the unit" In such a case% a test score of 6. woulprovie a goo cutoff score for etermining which pupils shoul procee with the unit anwhich shoul receive remeial help $efore proceeing" e woul% of course% prefer a largernum$er of pupils than thirty when selecting such cutoff scores% $ut this represents a realisticclassroom situation" As note earlier% it is frequently possi$le to increase the num$er of

pupils use in an expectancy ta$le $y com$ining test results from several classes"There is nothing in the nature of criterion)reference mastery testing to rule out construct

valiity" /o much of the supporting evience for construct valiity is epenent oncorrelations an other statistical measures% however% that the construct valiity of acriterion)reference test woul% of necessity% $e $ase on rather meager evience =i"e"% onlythat evience not epenent on varia$ility among scores>"

FACTOR# INFLUENCING VALIDIT"

1umerous factors ten to ma+e test results invali for their intene use" /ome are rathero$vious an easily avoie" 1o teacher woul thin+ of measuring +nowlege of socialstuies with an 3nglish test" 1or woul a teacher consier measuring pro$lem)solving s+illin thir)grae arithmetic with a test esigne for sixth graers" In $oth instances the testresults woul $e o$viously invali" The factors influencing valiity are of this same general

nature $ut much more su$tle in character" &or example% a teacher may overloa a socialstuies test with items concerning historical facts an thus it is less vali as a measure ofachievement in social stuies" ,r a thir)grae teacher may select appropriate arithmetic

pro$lems for his pupils $ut write irections that only the $etter reaers are a$le tounerstan clearly" The arithmetic test then $ecomes a reaing test which invaliates theresults for their intene use" This is the nature of some of the more su$tle factorsinfluencing valiity" These are the factors for which the teacher shoul $e alert% whetherconstructing classroom tests or selecting stanarie tests"

Factors in t$% T%st Its%l&

A careful examination of test items will inicate whether the test seems to measure thesu$'ect)matter content an the mental functions that the teacher is intereste in testing"

;owever% any of the following factors can prevent the test items from functioning asintene an there$y lower the valiity of the test results:5" #nclear directions. Directions which o not clearly inicate to the pupil how to

respon to the items whether it is permissi$le to guess an how to recor the answers

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6" &eading vocabulary and sentence structure too difficult. Voca$ulary an sentencestructure which is too complicate for the pupils ta+ing the test will result in the testmeasuring reaing comprehension an aspects of intelligence rather than the aspectsof pupil $ehavior that the test is intene to measure"

8" +nappropriate level of difficulty of the test items. In norm)reference tests% items whichare too easy or too ifficult will not provie relia$le iscriminations among pupils anwill therefore lower valiity" In criterion)reference tests% failure to match theifficulty of the test items with the ifficulty specifie in the instructional o$'ectiveswill lower valiity"

4" Poorly constructed test items. Test items which unintentionally provie clues to theanswer will ten to measure the pupils? alertness in etecting clues as well as theaspects of pupil $ehavior that the test is intene to measure"

@" "mbiguity. Am$iguous statements in test items contri$ute to misinterpretations anconfusion" Am$iguity sometimes confuses the $etter pupils more than the poorer

pupils% causing the items to function even less effectively for them"" $est items inappropriate for the outcomes being measured. Attempting to measure

unerstanings% thin+ing s+ills% an other complex types of achievement with testforms that are appropriate only for measuring factual +nowlege will invaliate theresults"

H" $est too short. " test is only a sample of the many questions that might $e as+e" If atest is too short to provie a representative sample of the $ehavior we are interestein% valiity will suffer accoringly"

" +mproper arrangement of items. Test items are typically arrange in orer of ifficultywith the easiest items first" 9lacing ifficult items early in the test may cause pupils tospen too much time on these an prevent them from reaching items they coul easilyanswer" Improper arrangement may also influence valiity $y having a etrimentaleffect on pupil motivation"

G" +dentifiable pattern of answers. 9lacing answers in some systematic pattern =e"g"% T% T%&% &% or A% -% 7% D% A% -% 7% D> will ena$le stuents to guess the answers to someitems more easily an this will lower valiity"

In short% any efect in the construction of the test which prevents the test items fromfunctioning in harmony with their intene use will contri$ute to the invaliity of themeasurement" #uch of what is written in the following chapters is irecte towarimproving the valiity of the results o$taine with classroom tests an other evaluationinstruments"

Functionin' Cont%nt an T%ac$in' Proc%ur%sIn the case of achievement testing% the functioning content of test items cannot $e

etermine merely $y examining the form an content of the test" &or example% thefollowing item may appear to measure arithmetical reasoning if examine without referenceto what the pupils have alreay $een taught:

If a 4.? pipe is cut so that the shorter piece is 6F8 as long as the longer piece% what isthe length of the shorter piece!

;owever% if the teacher has taught the solution to this particular pro$lem $efore givingthe test% the test item now measures no more than memorie +nowlege" /imilarly% tests ofunerstaning% critical thin+ing% an other complex learning outcomes are vali measures inthese areas only if the test items function as intene" If the pupils have previously $eentaught the solutions to the particular pro$lems inclue in the test% or have $een taught

mechanical steps for o$taining the solutions% such tests can no longer $e consiere valiinstruments for measuring the more complex mental processes"

Factors in T%st A(inistration an #corin'

The aministration an scoring of a test may also introuce factors that have aetrimental effect on the valiity of the results" In the case of teacher)mae tests% suchfactors as insufficient time to complete the test% unfair ai to iniviual pupils who as+ forhelp% cheating uring the examination% an the unrelia$le scoring of essay answers woulten to lower valiity" In the case of stanarie tests% failure to follow the stanarirections an time limits% giving pupils unauthorie assistance% an errors in scoringwoul similarly contri$ute to lower valiity" &or all types of tests% averse physical an

psychological conitions at the time of testing may also have a etrimental effect"

Factors in Pu)ils* R%s)ons%s

In some instances% invali test results are ue to personal factors influencing the pupil?s

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may $e hampere $y emotional istur$ances which interfere with their test performance"/ome pupils are frightene $y the test situation an there$y una$le to respon normally"/till others are not motivate to put forth their $est effort" These an other factors whichrestrict an moify pupils? responses in the test situation will o$viously lower the valiity ofthe test results"

A less o$vious factor which influences test results is that of response set.%%A response setis a consistent tenency to follow a certain pattern in responing to test items" &or example%some persons will respon BtrueB when they o not +now the answer to a true)false item%while other persons will ten to mar+ Bfalse"B A test with a large num$er of true statementswill consequently $e to the avantage of the first type of person an to the isavantage ofthe secon type" Although some response sets% such as the one illustrate% can $e offset $ycareful test construction proceures =e"g"% incluing an equal num$er of true an falsestatements in the test> other response sets are more ifficult to control" Typical of responsesets in this latter category are the tenency to wor+ for spee rather than accuracy% thetenency to gam$le when in ou$t% an the use of a particular style in responing to essaytests" These response sets reuce the valiity of the test results $y introucing into the testscore factors which are not pertinent to the purpose of the measurement" 56

Natur% o& t$% Grou) an t$% Crit%rion

Valiity is always specific to a particular group" An arithmetic test $ase on storypro$lems% for example% may measure reasoning a$ility in a slow group% an a com$ination

of simple recall of information an computational s+ill in a more avance group" /imilarly%scores on a science test may $e accounte for largely $y reaing comprehension in onegroup an $y +nowlege of facts in another" hat a test measures is influence $y suchfactors as age% sex% a$ility level% eucational $ac+groun% an cultural $ac+groun" Thus% inappraising reports of test valiity inclue in test manuals% or other sources% it is importantto note the nature of the valiation group" ;ow closely it compares in significantcharacteristics to the group of pupils we wish to test etermines how applica$le the in)formation is to our particular group"

In evaluating valiity coefficients% it is also necessary to consier the nature of thecriterion use" &or example% scores on a mathematics aptitue test are li+ely to provie amore accurate preiction of achievement in a physics course in which quantitative pro$lemsare stresse than in one where they play only a minor role" Li+ewise% we can expect scoreson a critical thin+ing test to correlate more highly with graes in social stuies courseswhich emphasie critical thin+ing than in those which epen largely on the memoriation

of factual information" ,ther things $eing equal% the greater the similarity $etween the$ehaviors measure $y the test an the $ehaviors represente in the criterion% the higher thevaliity coefficient"

/ince valiity information varies with the nature of the group teste an with thecomposition of the criterion measures use% pu$lishe valiation ata shoul $e consiereas highly tentative" henever possi$le% the valiity of the test results shoul $e chec+e inthe specific local situation"

This iscussion of factors influencing the valiity of test results shoul ma+e clear thepervasive an functional nature of the concept valiity" In the final analysis the valiity oftest results is $ase on the extent to which the $ehavior elicite in the testing situation is atrue representation of the $ehavior $eing evaluate" Tims% anything in the construction orthe aministration of the test which causes the test results to $e unrepresentative of thecharacteristics of the person teste contri$utes to lower valiity" In a very real sense% then% itis the user of the test who must ma+e the final 'ugment concerning the valiity of the test

results" ;e is the only one who +nows how well the test fits his particular use% how well thetesting conitions were controlle% an how typical the responses were to the testingsituation"of these influences can $e foun in the test instrument itself% some in the relation of teachingto testing% some in the aministration an scoring of the test% some in the atypical responsesof pupils to the test situation% an still others in the nature of the group teste an in thecomposition of the criterion measures use" A ma'or aim in the construction% selection% anuse of tests% an other evaluation instruments% is to control those factors which have anaverse effect on valiity an to interpret evaluation results in accorance with whatvaliity information is availa$le"

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#UMMAR"

The most important quality to consier when selecting ?or constructing an evaluation instrumentis valiity" This refers to the extent to which the evaluation results serve the particular uses forwhich they are intene" In interpreting valiity information% it is important to +eep in minthat valiity refers to the results rather than to the instrument% that its presence is a matter of

degree, an that it is alwaysspecific to some particular use"There are three $asic types of valiity" Content valiity refers to the extent to which a testmeasures a representative sample of the su$'ect)matter content an the $ehavioral changesuner consieration" It is especially important in achievement testing an is etermine $ylogical analysis of test content" Criterion-related valiity is concerne with the extent to whichtest performance is accurate in preicting some future performance or estimating some currentperformance" This type of valiity can $e reporte $y means of a correlation coefficient calle avaliity coefficient or $y means of an expectancy ta$le" It is of special significance in all typesof aptitue testing% $ut is pertinent whenever test results are use to ma+e specific preictions%or whenever a test is $eing consiere as a su$stitute for a more time)consuming proceure"Construct valiity refers to the extent to which test performance can $e interprete in terms ofcertain psychological constructs" The process of construct valiation involves ientifying anclarifying the factors which influence test scores so that the test performance can $e interpretemost meaningfully" This involves the accumulation of evience from a variety of ifferent

stuies" -oth of the other types of valiity may $e use as partial support for construct valiity%$ut it is the com$ine evience from all sources that is important" The more complete theevience% the more confient we are concerning the psychological qualities measure $y thetest"

-ecause criterion-referenced mastery tests are not esigne to iscriminate amonginiviuals% statistical types of valiity are inappropriate" &or this type of test% we must epenprimarily on content valiity" here the test scores are to $e use for preiction =e"g"% mastery)nonmastery>% an expectancy ta$le can $e effectively use"

A num$er of factors ten to influence the valiity of test results" /ome of these influencescan $e foun in the test instrument itself% some in the relation of teaching to testing% some in theaministration an scoring of the test% some in the atypical responses of pupils to the testsituation% an still other in the nature of the group taste an in the composition of the criterionmeasures use" A ma'or aim in the construction% selection an use of tests% an other evaluationinstruments% is to control those factors which have an averse effect on valiity an interpretevaluation results in accorance with that valiity information is availa$le"

validasi bab 4

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