Concepts of Validity PDF

VALIDITY Benedict B. Zulueta LEARNING OBJECTIVES Explain the concept of validity in the context of Psychological Testing. Compare and contrast the trinitarian view of validity. Evaluate the relationship of the concepts validity and reliability. Identify sources of bias that affects the vali...

VALIDITY Benedict B. Zulueta LEARNING OBJECTIVES Explain the concept of validity in the context of Psychological Testing. Compare and contrast the trinitarian view of validity. Evaluate the relationship of the concepts validity and reliability. Identify sources of bias that affects the validity of a test. THE CONCEPT OF VALIDITY Estimate of how well a test measures what it purports to measure in a particular context. Validity can be interpreted as acceptable or weak. No test is universally valid all the time The validity of a test must be proven again from time to time. Validity is the most important characteristic of a measuring instrument TRINITARIAN VIEW OF VALIDITY Content Validity Criterion-related Validity Construct Validity  FACE VALIDITY Term used to characterized tests that appear to measure what the test’s author desire to measure. Face validity pertains to whether the test looks valid to the examinees who take it and other technically untrained observers CONTENT VALIDITY A judgment of how adequately a test samples behavior representative of the universe is behavior that the test was designed to sample Content validation involves essentially the systematic examination of the test content to determine whether it covers a representative sample of the behavior domain to be measured. IMPORTANCE OF CONTENT VALIDITY Ensures Comprehensive Coverage Improves Test Credibility Supports Fair Assessment  CRITERION-RELATED VALIDITY A judgment of how adequately a test score can be used to infer an individual’s most probable standing on some measure of interest, the measure of interest being the criterion. CRITERION The standard against which a test or test score is Two types of Criterion-related Validity evaluated 1. Concurrent validity Characteristics of a criterion 2. Predictive Validity Relevant Valid Uncontaminated Criterion contamination is the term applied to a criterion measure that has been based, at least in part, on a predictor. CONCURRENT VALIDITY Test scores and related measures are collected at the same time. A test with good concurrent validity is appealing to users because: It can save money. It can save professional time.  Concurrent Validity can have 2 meanings: 1. It may refer to all kinds of information that can be CONCURRENT gained from the examinees within the representative VALIDITY sample of the target population at the very moment of test-taking 2. It is relevant for tests employed for diagnosis of existing status, rather than prediction of future outcomes.  IMPORTANCE OF CONCURRENT VALIDITY Comprehensive information gathering Diagnostic Accuracy Immediate Feedback PREDICTIVE VALIDITY Tells how well a certain measure can predict future behavior. Validity that is useful in prognosis. PREDICTIVE VALIDITY Base Rate - extent to which a particular trait, behavior, characteristic, or attribute exists in the population. Hit Rate - proportion of people accurately identified. Miss Rate - proportion of people the test fails to identify as having, or not having, a particular characteristic or attribute. STATISTICAL EVIDENCE Validity Coefficient A correlation coefficient that measures the relationship between test scores and scores on a criterion measure. Incremental Validity The degree to which an additional predictor explains something about the criterion measure that existing predictors do not explain  CONSTRUCT VALIDITY A judgment about the appropriateness of inferences drawn from test scores regarding individual standings on a variable called a construct. Construct An informed, scientific idea developed to describe or explain behavior Evaluating Construct Validity Hypothesis Formulation Theory Development Behavior Prediction Reevaluation  Homogeneity The test measures a single construct. Score Changes As predicted, test scores increase or decrease with age, time, or experimental manipulation. Evidence for Pretest-Posttest Differences Construct Scores differ before and after an event or over time as theoretically predicted. Validity Group Differences Scores vary among distinct groups as predicted by the theory. Correlations with Other Tests Test scores correlate with other tests' scores as predicted by the theory. Homegeneity Homogeneity refers to how uniformly a test measures a single concept. Methods to Increase Homogeneity Subtest Correlation Dichotomous Items Multipoint Scale Items Score Changes Some constructs change predictability over time. Evidence of Pretest–Posttest Changes Changes in test scores due to experiences like education, therapy, or job training support construct validity. Evidence from Distinct Groups Valid test scores should vary predictably based on group membership Convergent Evidence Convergent evidence comes from high correlations with other tests measuring the same or related constructs. Discriminant Evidence Discriminant evidence is shown by low correlations with tests measuring different constructs. Evidence from Distinct Groups Valid test scores should vary predictably based on group membership Convergent Evidence Convergent evidence comes from high correlations with other tests measuring the same or related constructs. Discriminant Evidence Discriminant evidence is shown by low correlations with tests measuring different constructs.