Sunday, July 5, 2009

Psychological Tests and Testing

Some Assumptions about Psychological Testing and Assessment:
Assumption 1: Psychological Traits and States Exist
Trait: Any distinguishable, relatively enduring way in which one individual varies from another
(specific intellectual abilities, cognitive style, interests, attitudes, sexual orientation)
Psychological Traits exist as a construct- an informed scientific concept developed or constructed to describe or explain behavior.
We can't see, hear or touch constructs but we can infer their existence from overt behavior
States: also distinguish one person from another but less enduring

Assumption 2: Psychological Traits and States Can Be Quantified and Measured
Traits and States need to be carefully defined
Consider the type of item content that would provide insight into it
Measuring traits and states by means of a test entails developing not only appropriate test items but also appropriate ways to score the test and interpret the results
Assumption 3: Test Related Behavior Predicts Non-Test-Related Behavior
Assumption 4: Tests and Other Measurement Techniques Have Strengths and Weaknesses
This is emphasized repeatedly in the codes of ethics of associations of assessment professionals.
Understand how a test was developed, circumstances under which it is appropriate to administer the test and to whom, and how the test results should be interpreted. Understand the limitations of the test and how limitations might be compensated for by data from other sources.
Assumption 5: Various Sources of Error Are Part of the Assessment Process
Error refers to a long-standing assumption that factors other than what the test attempts to measure will influence performance on the test
error variance: the component of a test score attributable to sources other than the trait of ability measured
Assumption 6: Testing and Assessment Can Be Conducted in a Fair and Unbiased Manner
Perhaps the most controversial
Assumption 7: Testing and Assessment Benefit Society
Considering the many critical decisions that are based on testing and assessment procedures,we can readily appreciate the need for tests

Psychometric Soundness of Tests:
Reliability: A perfectly reliable measuring tool consistently measures in the same way
Validity: A test is considered valid if it does in fact measure what it purports to measure

Classical or true score theory