IN PSYCHOLOGICAL TF.STS - ----L. J. CRONBACH and P. E. MEEID..----- validity seems only to have stirred the muddy waters. Portions of the distinctions we shall discuss are implicit in Jenkins' paper, "Validity for 'What?" { 33), Gulliksen's "Intrinsic Validity" (27), Goo

VALIDATION of psychological tests has not yet been adequately concep· Four Types of Validation tua1ized, as the APA Committee on Psychological Tests learned when TI1e categories into which the Recommendations divide validity it undertook (1950-54) to specify what qualities should be investigated studies are: predictive validity, concurrent validity, content validity, and before a is published. In order to make coherent recommendations constrnct validity. The first two of these may be considered together the Committee found it necessary to distinguish four types of validity, as criterion-oriented validation procedures. established by different types of research and requiring different interpre· TI1e pattern of a criterion-oriented study is familiar. The investigator tation. The chief innovation in the Committee's report was the term is primarily interested in some criterion which he wishes to predict. lie constmct validity.* This idea was first formulated hy a subcommittee administers the test, obtains an independent criterion measure on the {Meehl and R. C. Cballman) studying how proposed recommendations same subjects, and computes a correlation. If the criterion is obtained would apply to projective techniques, and later modified and clarified some time after tile test is given, he is studying predictive validity. If the by the entire Committee {Bordin, Challman, Conrad, Humphreys, test score and criterion score are determined at essentially the same Super, and the present writers). The statements agreed upon by tbe time, he is studying concurrent validity. Concurrent validity is studied Committee (and by committees of two other associations) were pub­ when one test is proposed as a substitute for another (for example, when lished in the Technical Recommendations ( 59). The present interpre­ a multiple-choice form of spelling test is substituted for taking dicta­ tion), or a test is shown to correlate with some contemporary criterion tation of construct validity is not "official" and deals with some areas (e.g., psychiatric diagnosis). in which the Committee would probably not be unanimous. The present Content validity is established by showing that the test items arc writers are solely responsible for this attempt to explain the concept a sample of a universe in whic11 the investigator is interested. Content and elaborate its implications. validity is ordinarily to be established deductively, by defining a uni· Identification of construct validity was not an isolated development. verse of items and sampling systematically within this universe to Writers on validity during the preceding decade had shown a great establish the test. deal of dissatisfaction with conventional notions of validity, and intro· Construct validation is involved whenever a test is to be interpreted dnced new terms and ideas, hut the resulting aggregation of types of as a m0<1sure of some attribute or quality which is not "operationally * Referred to in a preliminary report ( 58) as cougruent validity. defined." TI1e problem faced by the investigator is, ''\Vhat constn1cts NOTE: The second author worked on this problem in connection with his appoint· account for ·variance in test performance?" Construct validity calls for mcnt to the Minnesota Center for . \Ve are indebted to the other members of the Center (Herbert Feigl, l'vlichael Scriven, \.Vilfricl Sellars), and 110 new scientific approach. Much current research on tests of per­ h> D. L. Thistlcthwaitc of the University of Illinois, for their m;1jor c:o11trilmtions to sonnlity (9) is consl'ruct validation, usually without the benefit of a our thi11king a11c1 their suggestions for improving this paper. T he paper li rst appc;ll'l'·dwlogie:rl l311llcti11, July 1955, and is reprinted here, wi th minor :ilti;rations. hy pl' 1111 issio11 of Ilic editor :ind of the authors. Construct validity is not to he identified solely by particular investi- 174 175 L. J. Cronbach and P. E. Meehl CONSTRUCT VALIDITY IN PSYCHOLOGICAL TESTS gative procedures, but by the orientation of the investigator. Criterion­ is too coarse. It is obsolete. If we attempted to ascertain the validity oriented validity, as Bechtoldt emphasizes ( 3, p. 1245), "involves the of a test for the second space-factor, for example, we would have to acceptance of a set of operations as an adequate definition of whatever get judges [to] make reliable judgments ah<:>ut people as to this factor. is to be measured." \.Vhen an investigator believes that no criterion Ordinarily their [the available i.u~ges'] r~tm~s would b~. of no v~lue as a criterion. Consequently, vahd1ty studies m the cogmbve functions available to him is fully valid, he perforce becomes interested in con­ now depend on criteria of internal consistency ... (60, p. 3). struct validity because this is the only way to avoid the "infinite frus­ Construct validity would be involved in answering such questions as: tration" of relating every criterion to some more ultimate standard ( 21). To what extent is this test of intelligence culture-free? Does this test In content validation, acceptance of the universe of content as defining of "interpretation of data" measure reading ability, quantitative reason­ the variable to be measured is essential. Construct validity must be in­ ing, or response sets? How does a person with A in Strong Accountant, vestigated whenever no criterion or universe of content is accepted as and B in Strong CPA, differ from a person who has these scores entirely adequate to define the quality to be measured. Determining reversed? what psychological constructs account for test performance is desirable Example of construct validation procedure. Suppose measure X cor­ for almost any test. Thus, although the MMPI was originaJly estab­ relates .50 with Y, the amount of palmar sweating induced when we lished on the basis of empirical discrimination between patient groups tell a student that he has failed a I exam. Predictive validity and so-called normals (concurrent validity), continuing research has of X for Y is adequately described by the coefficient, and a statement tried to provide a basis for describing the associated with of the experimental and samp1ing conditions. If someone were to ask, each score pattern. Such interpretations permit the clinician to predict "Isn't there perhaps another way to interpret this correlation?" or performance with respect to criteria which have not yet been employed "\Vhat other kinds of evidence can you bring to support your interpre­ in empirical validation studies (cf. 46, pp. 49-50, 110-11). tation?" we would hardly understand 'vhat he was asking because no Vie can distinguish among the four types of validity by noting that interpretation has been made. These questions become relevant w~en each involves a different emphasis on the criterion. In predictive or con­ current validity, the criterion behavior is of concern to the tester, and the correlation is advanced as evidence that "test X measures anxiety he may have no concern whatsoever with the type of behavior exl1ibited proneness." Alternative interpretations are possible; e.g., perhaps the in the test. (An employer does not care if a worker can manipulate test measures "academic aspiration," in which case we will expect dif­ blocks, but the score on the block test may predict something he cares ferent results if we induce palmar sweating by economic threat. It is about.) Content validity is studied when the tester is concerned with then reasonable to inquire about other kinds of evidence. the type of bel1avior involved in the test performance. Indeed, if the test is a work sample, the behavior represented in the test may be an Add these facts from further studies: Test X correlates .45 with fra­ end in itself. Construct validity is ordinarily studied when the tester ternity brothers' ratings on "tenseness." Test X correlates .55 with has no definite criterion measure of the quality with which he is con­ amount of inteJlectual inefficiency induced by P'dinful electric shock, cerned, and must use indirect measures. Herc the trait or quality un­ and .68 with the Taylor Anxiety . Mean X score decreases among derlying the test is of central importance, rather than either the test four diagnosed groups in this order: anxiety state, reactive depression, behavior or the scores on the criteria ( p. 14). 59, "normal," and psychopathic personality. And palmar sweat under threat Construct validation is important at times for every sort of psycho­ of failure in Psychology I correlates .60 with threat of failure in mathc· logical test: aptitude, achievement, interests, and so on. Thurstone's matics. Negative results eliminate competing explanations of the X statement is interesting in this connection: score; thus, findings of negligible correlations between X and social In the field of intelligence tests, it used to be common to define validity class, vocational aim, and value-orientation make it fairly safe to reject as the correlation between a test score and some outside criterion. \Ve the suggestion that X measures "academic aspiration." We can have have reached a stage of sophistication where the test-criterion correlation substantial confidence that X docs lll<~a s ure anxiety proneness if the 176 177 L. J. Cronbach and P. E . Meehl CONSTRUCT VALIDITY IN PSYCHOLOGICAL TESTS current of anxiety can embrace the variates which yield positive The Relation of Constmcts to "Criteria" correlations, and does not predict correlations where we found none. CRITICAL VIEW OF' THE CRITERION IM PLIED An unquestionable criterion may be found in a practical operation, Kinds of Constructs or may be established as a consequence of an operational definition. At this point we should indicate summarily what we mean by a con­ Typically, however, the is unwilling to use the directly struct, recognizing that much of the remainder of the paper deals with operational approach because he is interested in building a theory about this question. A construct is some postulated attribute of people, a generalized construct. A theorist trying to relate behavior to "h unger" assumed to be reflected in test performance. In test validation the almost certainly invests that term with meanings other than the opera­ attribute about which we make statements in interpreting a test is tion "elapsed-time-since-feeding." If he is concerned with hunger as a a construct. We expect a person at any time to possess or not possess tissue need, he will not accept time lapse as equivalent to his construct a qualitative attribute (amnesia) or structure, or to possess some degree because it fails to consider, among other things, energy expenditure of a quantitative attribute {cheerfulness). A construct has certain asso­ of the animal. ciated meanings carried in statements of this general character: Persons who possess this attribute will, in situation X, act in manner Y (with In some situations the criterion is no more valid than the test. Sup­ a stated probability). The logic of construct validation is invoked pose, for example, that we want to know if counting the dots on Bender­ whether the construct is highly systematized or loose, used in ramified Ccstalt figure five indicates "compulsive rigidity," and that we take theory or a few simple propositions, used in absolute propositions or psychiatric ratings on this trait as a criterion. Even a conventional report probability statements. We seek to specify how one is to defend a on the resulting correlation will say something about the extent and proposed interpretation of a test; we are not recommending any one intensity of the psychiatrist's contacts and should describe his qualifica­ type of interpretation. tions (e.g., diplomatc status? analyzed?). The constructs in which tests are to be interpreted are certainly not \,Vhy report these facts? Because data are needed to indicate whether likely to be physiological. Most often they will be traits such as "latent the criterion is any good. "Compulsive rigidity" is not really intended hostility" or "variable in mood," or descriptions in terms of an educa­ to mean "social stimulus value to psychiatrists." The implied trait in­ tional objective, or "ability to plan experiments." For the benefit of volves a range of behavior-dispositions which may be very imperfectly readers who may have been influenced by certain exegeses of MacCor­ sampled by the psychiatrist. Suppose dot-counting does not occur in quodale and Meehl (40), let us here emphasize: Whether or not an a particular patient and yet we find that the psychiatrist has ra ted him interpretation of a test's properties or relations involves questions of as "rigid." 'Vhen questioned the psychiatrist tells us that the patient construct validity is to be decided by examining the entire body of w-as a rather easy, free-wheeling sort; however, the patient did lean over evidence offered, together with what is asserted about the test in the to straighten out a skewed desk blotter, and this, viewed against certain context of this evidence. Proposed identifications of constructs aJlegedly other facts, tipped the scale in favor of a "rigid" rating. On the face measured by the test with constructs of other sciences (e.g., genetics, of it, counting Bender dots may be just as good (or poor) a sample neuroanatomy, biochemistry) make up only one cJass of construct­ of the compulsive-rigidity domain as straightening desk blotters is. validity claims, and a rather minor one at present. Space does not Suppose, to extend om example, we have four tests on the "predictor" permit full analysis of the relation of the present paper to the Mac­ side, over against the psychiatrist's "criterion," and find generally posi­ Corquodalc-Meehl distinction between hypothetical constructs and in· tive correlations among the five variables. Surely it is artificial rmd arhi­ l'crvcning variables. The philosophy of science pertinent to the present t·rary to impose the "t·est·sliould-preclict-critcrion" pattern on !1 11d1 clala. paper is set forth later in the section entitled, "The nomological net· T he p.<>ychiatrist samples verbal content, cxpr~sivc pattern, voice, pos­ work." ture, etc. T he psychologist !lmnplcs verbal coutcnt, pcrc:cptio11, exprcs- 17R 179 L. J. Cronbach and P. E. Meehl CONSTRUCT VALIDITY IN PSYCHOLOGICAL TESTS sive pattern, etc. Our proper conclusion is that, from this evidence, the struct validity for clinical devices is concerned with making an estimate four tests and the psychiatrist all assess some common factor. of a hypothetical internal process, factor, system, structure, or state and 111e asymmetry between the "test" and the so-designated "criterion" ca~not ~xpect to find. a ~lea r unitary behavioral criterion. An attempt arises only because the terminology of predictive validity has become to identify any one cntenon measure or any composite as the criterion aimed at is, however, usually unwarranted (59, pp. 14-15) . a commonplace in test analysis. In this study where a construct is the central concern, any distinction between the merit of the test and This appears to conflict with arguments for specific criteria promi­ criterion variables would be justified only if it had already been shown nent at places in the testing literature. Thus Anastasi (2) makes many that the psychiatrist's theory and operations were excellent measures of statements of the latter character: "It is only as a measure of a speci­ the attribute. ficall y defined criterion that a test can be objectively validated at all . . . To cJaim that a test measures anything over and above its criterion is Inadequacy of Validation in Terms of Specific Criteria pure speculation" (p. 67) . Yet elsewhere this article supports construct The proposal to validate constructual interpretations of tests runs validation. Tests can be profitably interpreted if we "know the relation­ counter to suggestions of some others. Spiker and McCandless ( 57) ships between the tested behavior ... and other behavior samples, favor an operational approach. Validation is replaced by compiling state­ none of these behavior samples necessarily occupying the preeminent ments as to how strongly the test predicts other observed variables of position of a criterion" ( p. 75). with several partial interest. To avoid requiring that each new variable be investigated com­ criteria might be used to study whether a test measures a postulated pletely by itself, they allow two variables to collapse into one whenever "general learning ability." If the data demonstrate specificity of ability the properties of the operationally defined measures are the same: "If instead, such specificity is "useful in its own right in advancing our a new test is demonstrated to predict the scores on an older, wcll­ knowledge of behavior; it should not be construed as a weakness of establishcd test, then an evaluation of the predictive power of the older the tests" (p. 75). test may be used for the new one." But accurate inferences are possible \Ve depart from Anastasi at two points. She writes, "The validity of only if the two tests correlate so h ighly that there is negligible reliable a psychological test should not be confused with an analysis of the variance in either test, independent of the other. Where the corre­ factors which determine the behavior under consideration." W e, how­ spondence is less close, one must either retain all the separate variables ever, regard such analysis as a most important type of validation. Second, operationally defined or embark on construct validation. she refers to "the will·o'-the-wisp of psychological proce~ses which arc The practical user of tests must rely on constructs of some generality distinct from performance" (2, p. 77). While we agree that psychologi­ to make predictions about new situations. Test X could be used to cal processes are elusive, we are sympathetic to attempts to formulate predict palmar sweating in the face of failure without invoking any and clarify constructs which are evidenced by performance but distiuct construct, but a counselor is more likely to be asked to forecast behavior from it. Surely an inductive inference based on a pattern of corrclatio11s in diverse or even unique situations for which the correlation of test X cannot be dismissed as "pure speculation." is unknown. Significant predictions rely on knowledge accumulated around the generalized construct of anxiety. The Technical Recom­ SPECIFIC CRITERIA USED TEMPORARILY: THE "BOOTSTRAPS" F.Jl'Fl•:CT mendations state: Even when a test is constructed on the basis of a specific cri1·crio11 , It is ordinarily necessary to evaluate construct validity by integrating it may ultimately be judged to have greater construct valiclil'y than Ihe evidence from many different sources. The problem of construct valida­ criterion. We start with a vague concept which we associate with cc1tai11 tion hccomes especially acute in the clinical field since for many of the observations. We then discover empirically that these ohservntio11s co11strncts dealt with it is not a question of finding an imperfect criterion co-vary with some other observation which possesses greater reliability h11I of finding any criterion at all. The psychologist interested in ('011 · or is more intimately correlated with relevant experimental chnn gc.~ than 180 181 L. f. Cronbach and P. E .- Meelil CONSTRUCT VALIDITY IN PSYCHOLOGICAL TESTS is the original measure, or both. For example, the notion of temperature Attitude Toward the Church by showing score differences between arises because some objects feel hotter to the touch than others. The church members and nonchurchgoers. Churchgoing is not tbe criterion expansion of a mercury column does not have face validity as an index of attitude, for the purpose of the test is to measure something other of hoh1ess. But it turns out that (a) there is a statistical relation be­ than the crude sociological fact of church attendance; on the other hand, tween expansion and sensed temperature; (b) observers employ the failure to find a difference would have seriously challenged the test. mercury method with good interobserver agreement; ( c) the regularity Only coarse correspondence between test and group designation is of observed relations is increased by using the thermometer {e.g., melt­ expected. Too great a correspondence between the two would indicate ing points of samples of the same material vary little on the thermome­ that the test is to some degree invalid, because members of the groups ter; we obtain nearly linear relations between mercury measures and are expected to overlap on the test. Intelligence test items are selected pressure of a gas). Finally, ( d) a theoretical structure involving unob­ initially on the basis of a correspondence to age, but an item that corre­ servable microevents-the kinetic theory-is worked out which explains lates .95 with age in an elementary school sample would surely be suspect. the relation of mercury expansion to heat. 111is whole process of con­ Correlation matrices and factor analysis. If two tests are presumed to ceptual enrichment begins with what in retrospect we see as an ex­ measure the same construct, a correlation between them is predicted. tremely fallible "criterion"-the human temperature sense. That original (An exception is noted where some second attribute has positive load­ criterion has now been relegated to a peripheral position. \Ve have lifted ing in the first test and negative loading in the second test; then a low ourselves by our boostraps, but in a legitimate and fruitful way. correlation is expected. 111is is a testable interpretation provided an Similarly, the Binet scale was first valued because children's scores external measure of either the first or the second variable exists.) If the obtained correlation departs from the expectation, however, there is no tended to agree with judgments by schoolteachers. If it had not shown way to know whether the fault lies in test A, test or the formulation this agreement, it would have been discarded along with reaction time B, of the construct. A matrix of intercorrclations often points out profitable and the other measures of ability previously tried. Teacher judgments ways of dividing the construct into more meaningful parts, factor once constituted the criterion against which the individual intelligence analysis being a useful computational method in such studies. test was validated. But if today a child's IQ is 135 and three of his Guilford (26 ) has discussed the place of factor analysis in construct teachers complain about how shtpid he is, we do not conclude that validation. H is statements may be extracted as fo11ows: "The personnel the test has failed. Quite to the contrary, if no error in test procedure psychologist wishes to know 'why his tests are valid.' He can place tests can be argued, wc treat the test score as a valid statement about an and practical criteria in a matrix and factor it to identify 'real dimen­ important quality, and define our task as that of finding out what other sions of human personality.' A factorial description is exact and stable; variables-personality, study skills, etc.-moclify achievement or distort it is economical in explanation; it leads to the creation of pure tests teacher judgment. which can be combined to predict complex behaviors." It is clear that factors here function as constructs. Eysenck, in his "criterion analysis" Expcrjmentation to Investigate Construct Validity (18), goes farther than Guilford, and shows that factoring can be used VALIDATION PROCEDURES explicitly to test hypotheses about constructs. '\Ve can use many methods in constrnct validation. Attention should Factors may or may not be weighted with surplus meaning. Certainly particnlarly be dra\.vn to Macfarlane's survey of these methods as they when they a;e regarded as "real dimensions" a great deal of surplus apply to projective devices ( 41) . meaning is implied, and the interpreter must shoulder a s11hs ta11tial Croup