Translation and equivalence assessment for a Japanese version of the modified Parental Nurturance Scale: a comparative study

BACKGROUND: This paper reports on the modification of the Parental Nurturance Scale (PNS), translation of the modified version (PNSM) from English to Japanese, and equivalence assessment between the PNSM and the translated version (PNSM-J). The PNS was modified so as to enable its use in nurturance studies where the prime source of nurturance might vary between respondents. METHOD: It was translated into Japanese through the forward-backward translation procedure. With attempting to enhance representativeness of language in the target populations, translators used were married couples that consisted of a native English speaker and a native Japanese speaker. Multiple translations were produced and used to make a single Japanese version. A panel of reviewers identified problems in conceptual and semantic equivalence between the original and the translated versions. The Japanese version was altered accordingly with reference to alternate Japanese forms from the original English to Japanese translations. The altered translation was again re-translated into English and problematic differences were checked. This forward-backward process was repeated until satisfactory agreement was attained. The PNSM was administered to 222 native English speakers and the PNSM-J to 1320 native Japanese speakers. RESULTS: Factor analysis and target rotation revealed a nearly identical factor structure and factor loadings of the items of the PNSM and PNSM-J between the different cultural groups. High Cronbach's alpha coefficient supported the reliability of the test scores on both versions. CONCLUSION: The equivalence between the two scales was supported. It is suggested that the PNSM and PNSM-J are suitable tools for comparative cross-cultural studies.