Evaluating Measurement Invariance Over Time for a Personal Opportunities Scale for People With IDD: Implications for...

Area of Science:

• Social Sciences
• Psychology
• Disability Studies

Background:

• Personal opportunities are crucial for self-directed action among individuals with intellectual and developmental disabilities (IDD).
• Assessing the consistency of measurement tools over time is vital for accurate longitudinal research.
• The COVID-19 pandemic introduced unique challenges that may have influenced self-perception and survey responses.

Purpose of the Study:

• To test for measurement invariance of the Personal Opportunities scale over a five-year period.
• To determine if the scale performed consistently across different time points, including during the COVID-19 pandemic.
• To evaluate changes in National Core Indicators In-Person Survey (NCI-IPS) outcomes.

Main Methods:

• Utilized five years of cross-sectional data for measurement invariance testing.
• Employed statistical analyses to examine scale performance over time.
• Assessed partial threshold and loading invariance, while testing for intercept invariance.

Main Results:

• Significant differences were found in both NCI-IPS outcomes and the Personal Opportunities scale over the five-year period.
• Measurement invariance testing revealed partial threshold and loading invariance.
• Intercept invariance was not achieved, indicating changes in how participants perceived or responded to scale items.

Conclusions:

• The Personal Opportunities scale did not demonstrate full measurement invariance over the study period.
• Changes in participant perception or response patterns over time necessitate careful interpretation of longitudinal data.
• Researchers using scaled measures with longitudinal data should implement statistical checks like measurement invariance testing to ensure data integrity.