Presentation on theme: "Controversy Surrounding Modern Validity Theory Dr Paul E. Newton Director, Cambridge Assessment Network Division Cambridge Assessment Paper presented to."— Presentation transcript:
Controversy Surrounding Modern Validity Theory Dr Paul E. Newton Director, Cambridge Assessment Network Division Cambridge Assessment Paper presented to SQA Research Seminar 11/11/11, Glasgow
Why is validity important? Validity is a (if not the) hallmark of quality for educational assessment A declaration of validity provides a green light to use an assessment procedure for the purpose at hand... a declaration of invalidity presents a red light
Q1: Can you date this quote? Two of the most important types of problems in measurement are those connected with the determination of what a test measures, and of how consistently it measures. The first should be called the problem of validity, the second, the problem of reliability.
Q2: Can you identify either series? Series 1 1951 1971 1989 2006 Series 2 1954 1966 1974 1985 1999
Theoretical revolution From fragmented conception of validity (Trinitarian) to an holistic one (Unitarian) Championed by Samuel Messick Between mid-1970s and late-1980s
The 1920s definition By validity is meant the degree to which a test or examination measures what it purports to measure. (Ruch, 1924, p.13)
Validity is conditional Upon having observed procedural guidelines –e.g. a well-developed test that had been administered incorrectly would not necessarily produce accurate results Upon the context of administration –e.g. a well-developed test designed in one decade would not necessarily produce accurate results two decades later Upon characteristics of the group assessed –e.g. a well-developed test of reading comprehension designed for 16-year-olds would not necessarily produce accurate results for 11- year-olds Upon the use(s) to which results are to be put –e.g. a well-developed test designed for selection would not necessarily produce accurate results for placement.
Contra 1920s definition For any test, validity may differ –if procedural guidelines are not followed –for different groups –within different contexts –when different interpretations (using different constructs) are made, for different uses So the test cannot be valid or invalid, only the interpretation of results. Each important interpretation needs to be validated in its own right.
The 1950-1970s conception Different kinds of validity, requiring different kinds of validation, apply to different kinds of testing. For curriculum-based testing: –content validity needs to be demonstrated –content validation is the appropriate method If there is satisfactory alignment between the content of the test and the content of the curriculum then the test is valid.
Mono-validation insufficient Even for testing educational attainment, content validation (to check adequate sampling of content) is insufficient –content validation can only help to validate inferences concerning students who score maximum marks –the way that questions present content may prevent them from eliciting the intended KSU evidence –the way that questions are marked may prevent evidence of KSU from being rewarded appropriately –different students will use different kinds of KSU to answer the same question –inferences are drawn in terms of constructs (e.g. X is better at scientific reasoning than Y) and even these construct labels need validating
Its all about construct validity [...] the profession is coming around to the view that all validation is construct validation. (Cronbach, 1984, p.126) [...] construct validity may ultimately be taken as the whole of validity in the final analysis. (Messick, 1989, p.21)
Double whammy! Rejection of 1920s definition: –for any given test, multiple interpretations will need to be validated (particularly when the same test is used for multiple purposes) Rejection of 1950-1970s conception: –for any given interpretation, multiple validation activities will be required to establish its (construct) validity
The last word on validity? Despite talk of a general consensus over the central tenets of modern validity theory: –substantial ambiguity over detail of the theory –ongoing resistance to putting it into practice –growing debate over its plausibility
1a. Ambiguity – meaning Miller et al (2009), on a single page (p.104), refer to: –the validity of an assessment –the validity of the assessment for that use or interpretation –the validity of interpretations of tests and assessments –the validity of test and assessment results –the validity of the uses and interpretations
1a. Ambiguity – meaning Which is the proper referent of validity? –the interpretation of the score (i.e. the claim) is valid –the use of results (i.e. the decision) is valid –the inferential process (assessment procedure) is valid –the intended, or actual, inferences from results are valid –the argument for interpreting and using results is valid –the inferential links within the argument chain are valid –the validation research conclusions are valid –the hypothesis is valid –the explanation is valid
1b. Ambiguity – evidence Relevance –is every kind of evidence/analysis relevant to every validation? Necessity –is every kind of evidence/analysis required for every validation?
Relevance and necessity Therefore, the profession is coming around to the view that all validation is construct validation. [...] Content- and criterion-based arguments develop parts of the story. With almost any test it makes sense to join all three kinds of inquiry in building an explanation. The three distinct terms do no more than spotlight aspects of the inquiry. (Cronbach, 1984, p.126)
Relevance and necessity [...] test validity cannot rely on any one of the supplementary forms of evidence just discussed. But neither does validity require any one form, as long as there is defensible convergent and discriminant evidence supporting test meaning. To the extent that some form of evidence cannot be developed [...] heightened emphasis can be placed on other evidence [...] What is required is a compelling argument that the available evidence justifies the test interpretation and use, even though some pertinent evidence had to be forgone. (Messick, 1998, pp.70-71)
Relevance and necessity [...] if the proposed interpretation of test results relies on predictions of future performance, these predictions should be empirically evaluated as part of the validation of the proposed interpretation; if no such predictions are made, no evidence for predictive accuracy is called for. (Kane, 2008, p.79)
2. Resistance – validation Well-established disjunction between modern validity theory and contemporary validation practice –Jonson & Plake (1998) –Hogan & Agnello (2004) –Cizek et al (2008) –Wolming & Wikstrom (2010)
2. Resistance – validation Validation has become very demanding... –multiple validation foci –multiple validation constructs –multiple uses of results
Multiple validation foci If were not just checking test content against curriculum content, for each test, what else do we need to do for each test? –OCR > A level > physics > version A > 2011 certification How much additional validation is required for distinct subgroups of the population? –ethnicity, class, gender, region, school, etc.
3a. Debate – good/bad impacts Can bad impacts, from otherwise good tests, really undermine validity? –when test used for intended purpose? –when test used for unintended purposes? Must developers provide evidence that their tests have had (or will have) good impacts? –is it really their responsibility? –how could evidence be collected in advance? –who ought to judge what counts as a good or bad impact?
3b. Debate – unitary concept Borsboom, et al (2004) –the test is valid (after all) Lissitz & Samuelsen (2007) –attainment tests dont require much more than content validation Murphy (2009) –aptitude tests dont require much more than criterion validation
My modern validity theory 1.Technical standard validity of (each) use of results – depends on strength of argument for interpreting those results in terms of the validation construct (includes reliability) 2.Ethical standard defensibility (includes social policy, i.e. good/bad impacts) 3.Legal standard legality 4.Economic standard feasibility 5.Political standard acceptability (includes face validity)