[Development of a Japanese version of the Interpersonal Reactivity Index]

Area of Science:

• Psychology
• Social Psychology
• Personality Psychology

Background:

• Empathy is a complex, multi-dimensional trait encompassing emotional and cognitive aspects.
• Existing Japanese translations of the Interpersonal Reactivity Index (IRI) have shown limitations in validity and measurement invariance.
• A reliable and valid measure of empathic traits is crucial for research within the Japanese population.

Purpose of the Study:

• To develop and validate a new Japanese version of the Interpersonal Reactivity Index (IRI-J).
• To overcome the limitations of previous Japanese IRI translations.
• To provide an improved instrument for assessing empathic traits in Japan.

Main Methods:

• Study 1: Assessed content validity via back-translation and construct validity using a web-based survey with six other scales.
• Study 2: Confirmed measurement invariance across genders using data from four web-based surveys.
• Employed rigorous statistical approaches to ensure the psychometric properties of the IRI-J.

Main Results:

• The IRI-J exhibited a factor structure equivalent to the original IRI.
• Adequate reliability and construct validity were confirmed for the IRI-J.
• Measurement invariance by gender was established, indicating equivalent factor models across genders.

Conclusions:

• The newly developed IRI-J is a psychometrically sound measure of empathic traits for the Japanese population.
• The IRI-J addresses previous limitations, offering enhanced validity and reliability.
• This validated instrument will facilitate future research on empathy in Japan.