Reading focus
Syllabus: How Do We Know What a Psychological Test Measures?
Distinguish the meaning of the Persistence Scale’s scores from proposed actions based on them, and notice how Messick relates both to evidence.
Why you’re reading it. Make the scope of a validity argument explicit, including its implications for use.
A question to consider. What additional justification would be needed to use the scale to allocate tutoring rather than simply study an association with completion?
Why this reading
Messick connects evidence about score meaning with the uses made of scores. His unified account asks how content, response processes, structure, generalization, external relationships, and consequences contribute to a defensible interpretation.
Before you read
Construct underrepresentation means leaving out relevant parts of an attribute. Construct-irrelevant variance means that other influences affect the score. An interpretation states what a score means; a use specifies the action it informs.
Read for
- Track what unifies Messick’s six aspects of validity rather than treating them as independent certificates.
- Distinguish adverse consequences arising from measurement problems from consequences of a policy using an otherwise defensible interpretation.
- Identify where theoretical reasoning, empirical evidence, and value judgments enter the argument.
Consider afterwards
- A school uses a reasoning test to allocate tutoring. Which evidence would address score meaning, and which would address the proposed use?
Editorial context
This is an influential position within a continuing conceptual debate. Borsboom and colleagues defend a narrower causal account. Messick’s inclusion of consequences should not be reduced to the claim that every undesirable outcome makes a test invalid.