SSM® Psychometric Results

The SSM® Assessment has been developed and independently evaluated through two professional psychometric reports.

Report 1 — Content & Face Validity (2025)

Prepared by Dr. E. Talavera Escribano, this report documents the assessment's development and qualitative validation, including:

• Expert-led item design and refinement under a Lead Psychometrician.
• International panel of Subject Matter Experts evaluation of items for relevance, clarity, and construct coverage using Content Validity Index (CVI) procedures.
• Diverse end-user pilot evaluated comprehensibility and acceptability (face validity), followed by targeted refinements to reduce cognitive load.
• Alignment with recognised professional standards, including the APA Standards for Educational and Psychological Testing, ITC Guidelines, ISO 10667-2, and APS/ACER guidance.

Report 2 — Psychometric Evaluation (2026)

Prepared by M. Abbas, this report evaluated responses from 349 participants collected through the Prolific research platform. The evaluation included:

• Bayesian multidimensional Thurstonian Item Response Theory (TIRT) calibration.
• Construct differentiation (ensuring each strength measures a distinct construct).
• Trait reliability estimation.
• Exploratory structural diagnostics.
• Differential item functioning (DIF) analysis.
• Preliminary norm development.

The report concluded: “Overall, the SSM forced-choice strengths instrument demonstrates a methodologically appropriate psychometric foundation." Further highlights of the report may be found here. Following this evaluation, a number of assessment items were refined to improve clarity, fairness and measurement quality. A follow-up psychometric evaluation of the updated assessment is planned.