Effects of Questionnaire Translation on Demographic Data and Analysis

The collection of demographic data in developing and, increasingly, developed countries often requires the translation of a survey instrument. This article addresses the implications for data and analysis of two of the most common modes of translation. The first, the officially sanctioned--though not empirically verified--method, involves the pre-fieldwork production of a standardized translation of the template questionnaire into all or most languages in which interviews are expected to be conducted. The second, rarely acknowledged in the literature but quite common in the field, occurs where there is a mismatch between the language of the questionnaire available to the interviewer and the language in which the actual interview is conducted. In this case, it is up to the interviewer to translate from the language of the questionnaire to the language of the interview. Using the 1998 Kenya DHS, in which 23% of interviews were translated in this non-standardized manner, we explore the effects of the two translation modes on three indicators of measurement error and on estimated multivariate relations. In general we find that the effects of non-standardized translation on univariate statistics--including higher-order variance structures--are rather moderate. The effects become magnified, however, when multivariate analysis is used. This suggests that the advantages of--and also costs associated with--standardized translation depend on the ultimate purposes of data collection.