How reliable are reports of early adolescent reproductive and sexual health events in demographic and health surveys?

The health and well-being of female adolescents is considered crucial to the continued development of low-income countries. (1) Among the most widely used indicators of health and well-being for female adolescents are age at sexual debut (also described as age at first sex), age at first marriage or first union and age at first birth. Demographic and Health Survey (DHS) data are widely used to estimate these indicators, and DHS country reports routinely present the percentage of women aged 15-49 who experience sexual debut, marry or give birth before age 15, grouped into five-year cohorts, and the percentage of women aged 15-19 at time of survey who have started childbearing, by individual year of age. Despite evidence suggesting that social desirability bias and recall bias may exert a strong influence on reports of childbearing, sexual debut and marriage by adolescents, (2-4) the accuracy of DHS-based estimates of these widely reported indicators is poorly understood. Even less is known about the reliability of data when these events occur in very early adolescence. There is widespread recognition of the vulnerability of and risks faced by sexually active young adolescents (both in or outside of marriage), (5) and growing understanding of the need for appropriate sexual health education and services for this age-group. (6) To support improvements in education and services, age-disaggregated indicators are required to identify need and monitor progress. However, inaccurate data may lead to erroneous interpretations of both the proportions of adolescents experiencing sexual health events and of trends over time. In particular, underestimations of the proportions affected or overestimation of positive trends could lead to complacency about the scale of the problem or false optimism over progress. In this article, we first examine the consistency of DHS data from two consecutive surveys in each of nine countries on adolescent age at sexual debut, marriage or first union, and first birth across cohorts, disaggregated by age in years. We then carry out further analysis to determine which age-group of respondents (ages 15-19 vs. 20-24) is most likely to provide the most accurate estimates. In the discussion, we consider possible underlying causes for the inconsistencies we have identified and the implications the inconsistencies have for policymakers and researchers who use these data. Sources of Errors The DHS relies on retrospective reporting of events and asks all responding women of reproductive age to report on the same events, e.g., age at sexual debut, age at first marriage or union, and age at first birth. Errors in reporting on reproductive and sexual health events can be divided into three categories: recall error, survey completion issues and social desirability bias. While some of these sources of error are universal, others may be more prevalent in particular age-groups. Recall bias, an unintentional error in which an event is omitted or mistimed, is more common among older women than among younger women because more time has elapsed between the survey and the event of interest. (7) Perceptions of an event such as first marriage or union may be another source of unintentional error because the cultural, social and legal conditions defining such an event may vary. (8,9) Marriage and union formation may be fluid and, in many countries, are processes rather than single events, often spread out over many years. (10-13) Responses to questions on the occurrence and timing of marriage or union formation will reflect the current perceptions of respondents when thinking back over the course of their lives, and these perceptions may change as women get older. Survey completion issues may be a source of intentional bias. In the DHS, the backdating of births is a common problem because respondents who have given birth within five years of the survey are required to complete an additional questionnaire for the child. …