STM Article Repository

Background: The EASI (measuring Emotionality, Activity, Sociability and Impulsivity) is a widely used
instrument to measure children’s temperament. However, its factor structure and its measurement
and structural invariances have rarely been studied. The purpose of our study is to report the factor
structure of the EASI in a larger population in Japan searching for the model that fits the data
sufficiently as well as the final model’s measurement and structural invariance.
Methods: A net-survey collected data from 531 mothers and 369 fathers of 3- to 4-year-old Japanese
children. A test-retest survey was conducted of 173 mothers and 127 fathers out of the first group of
participants.
Results: The original 4-factor structure (excluding 6 items) with a general factor (influencing E and I)
showed an acceptable fit. This model also satisfied measurement and structural invariance between
fathers and mothers, boys and girls, 3- and 4-year-old, and times 1 and 2. Differences emerged
between mothers and fathers in terms of the means of some factor scores.
Conclusion: Our study found that the EASI’s factor structure was invariant in terms of parent and
children’s gender, children’s age and measurement occasions. This is encouraging as it allows the
EASI to be used in clinical as well as research settings. We recommend the use of 4 subscale scores
as well as a compo-site score of E and I.