Reading focus
Syllabus: How Do We Know What a Psychological Test Measures?
Connect each level of invariance with the comparison it is meant to support, keeping the model’s assumptions visible.
Why you’re reading it. Understand why identical questions or translations do not automatically produce comparable measurements.
A question to consider. One Persistence Scale item concerns studying alone. What evidence would you need before comparing students in settings where study is usually solitary versus collaborative?
Why this reading
Using the same questions does not ensure comparable score meanings. This review explains why comparisons across groups or occasions require evidence about the relationship between a construct and its indicators.
Before you read
A factor loading connects an indicator to a modeled factor. An intercept represents its expected level when the factor is zero. Invariance asks whether specified measurement parameters can be treated as equal across groups or occasions.
Read for
- Distinguish configural, metric, scalar, and residual invariance by what each constrains.
- Connect each comparison of interest with the assumptions it needs.
- Notice disagreement about fit criteria and partial invariance rather than treating thresholds as universal guarantees.
Consider afterwards
- A programme changes how participants interpret one questionnaire item. How could that complicate a claim that its average score improvement represents psychological change?
Editorial context
This is a review of conventions and reporting at its publication date, centered on confirmatory factor analysis. It is not a timeless set of statistical cutoffs. Noninvariance calls for investigating which comparisons remain defensible; invariance within a model does not, by itself, establish fairness or complete construct validity.