Adaptation and validation of the Intrinsic Motivation Inventory (IMI) in Polish

Area of Science:

• Psychology
• Cross-cultural psychology
• Psychometrics

Background:

• The Intrinsic Motivation Inventory (IMI) is a widely used measure of motivation.
• Adapting and validating psychological instruments across languages is crucial for cross-cultural research.
• Assessing measurement invariance ensures that constructs are understood similarly across different linguistic groups.

Purpose of the Study:

• To adapt the full 45-item, seven-subscale Intrinsic Motivation Inventory (IMI) into Polish.
• To evaluate the psychometric properties of the Polish IMI.
• To examine cross-language measurement invariance between the Polish and English versions of the IMI in bilingual individuals.

Main Methods:

• Two independent online samples (N=275) of Polish-English bilinguals completed the IMI in both languages.
• Reliability (Cronbach's alpha, McDonald's omega), cross-language correlations, and confirmatory factor analyses (CFA) were performed.
• Measurement invariance was tested using a CT-C(M-1) framework, comparing configural and strict metric models. Convergent and divergent validity were assessed.

Main Results:

• Confirmatory factor analysis supported the seven-factor structure for the IMI in both Polish and English, with good model fit.
• Language invariance analysis revealed minimal configural-metric differences, indicating approximate measurement invariance.
• The Polish IMI demonstrated strong internal consistency and subscale-level equivalence with the English version, supporting its construct validity.

Conclusions:

• The adapted Polish Intrinsic Motivation Inventory (IMI) is psychometrically sound and suitable for research with Polish-speaking populations.
• The study provides evidence for approximate measurement invariance between the Polish and English versions of the IMI.
• Open availability of materials, data, and analysis code facilitates future research and replication.