Purpose: This study aimed to create a Japanese version of the eight-item version of modified medical outcomes study social support survey (mMOS-SS), investigate psychometric property, and determine the standard values for Japanese citizens by using a nationally representative sample from the general population.
Methods: A stratified two-stage sampling was conducted with 4000 Japanese men and women who were in the age group of 25-74 as of January 01, 2014. From February to March 2014, placement method was conducted using self-administered questionnaire. Consequently, 2067 questionnaires were gathered (a collection rate of 51.7%). Thus, the target of analysis was 952 males and 1100 females.
Results: The results of factor analysis showed that each of the samples exhibited two types of factors, i.e., emotional and instrumental, just as was the case with the original version. The Cronbach's alpha ranged from 0.90 to 0.95 for each of the samples for both total score and the subscales. On comparing the groups by married versus unmarried and living alone versus not living alone, those not living alone and married people had significantly higher scores (p < 0.05) for each group except for married females less than 50 years. There was a significant positive correlation among mental health, life satisfaction, and self-rated health.
Conclusion: This study revealed that the eight-item Japanese version of the mMOS-SS had the same psychometric properties as those found in the research results of the English version.
Keywords: Japan; National representative sample survey; Psychometric property; Scale development; Social support.