Scale Development and Psychometrics
We run the whole scale development and adaptation process, from the item pool through to measurement invariance, and report the validity and reliability evidence.
What we do
Item pool and content validity. Item writing, collection of expert opinion, and computation of content validity ratios.
Construct validity. Exploratory factor analysis to discover the structure and confirmatory factor analysis to test it, with goodness-of-fit indices interpreted rather than merely listed.
Reliability. Internal consistency coefficients, test-retest reliability and item-total correlations.
Measurement invariance. Where groups or time points are to be compared, configural, metric and scalar invariance are tested.
Adaptation studies. After translation and back-translation, linguistic and cultural validity are demonstrated statistically.
What sets us apart
Invariance before comparison. Comparing group means with a scale whose invariance has not been shown leaves it unclear whether the difference comes from the groups or from the instrument.
Every choice is justified. The number of factors, the rotation and the estimation method are reported with their rationale.
We stay with the project. In thesis and journal work, the answers to reviewer questions are part of the job.
There is a matching surface in Basira. A substantial part of the scale development workflow can be run by you in the Psychometrics Studio.