Stéphane Helleringer and colleagues conducted a validation study in Niakhar, Senegal to investigate whether a new approach, sibling survival calendars, improves the quality of adult mortality data collected in demographic surveys.
Please see later in the article for the Editors' Summary
In countries with limited vital registration, adult mortality is frequently estimated using siblings' survival histories (SSHs) collected during Demographic and Health Surveys (DHS). These data are affected by reporting errors. We developed a new SSH questionnaire, the siblings' survival calendar (SSC). It incorporates supplementary interviewing techniques to limit omissions of siblings and uses an event history calendar to improve reports of dates and ages. We hypothesized that the SSC would improve the quality of adult mortality data.
Methods and Findings
We conducted a retrospective validation study among the population of the Niakhar Health and Demographic Surveillance System in Senegal. We randomly assigned men and women aged 15–59 y to an interview with either the DHS questionnaire or the SSC. We compared SSHs collected in each group to prospective data on adult mortality collected in Niakhar. The SSC reduced respondents' tendency to round reports of dates and ages to the nearest multiple of five or ten (“heaping”). The SSC also had higher sensitivity in recording adult female deaths: among respondents whose sister(s) had died at an adult age in the past 15 y, 89.6% reported an adult female death during SSC interviews versus 75.6% in DHS interviews (p = 0.027). The specificity of the SSC was similar to that of the DHS questionnaire, i.e., it did not increase the number of false reports of deaths. However, the SSC did not improve the reporting of adult deaths among the brothers of respondents. Study limitations include sample selectivity, limited external validity, and multiple testing.
The SSC has the potential to collect more accurate SSHs than the questionnaire used in DHS. Further research is needed to assess the effects of the SSC on estimates of adult mortality rates. Additional validation studies should be conducted in different social and epidemiological settings.
Please see later in the article for the Editors' Summary
Governments and international health agencies need accurate information on births and deaths in populations to help them plan health care policies and monitor the effectiveness of public health programs. The most common way of collecting information on vital statistics in an area or country is through civil registration, an administrative system used by governments to record vital events that occur in their populations. In low-to-middle-income countries that have limited resources to devote to such a system, unconventional techniques are often used to estimate mortality levels and trends. One such method is siblings' survival histories collected while conducting a health or other type of public survey. Those surveyed are asked to list all their maternal siblings by birth order and report survival status and current age (for living siblings) or age at death (for deceased siblings).
Use of siblings' survival histories leaves the accuracy of the mortality record vulnerable to reporting errors and selection bias. Selection bias is a statistical prejudice that is introduced by the choice of the individuals or groups taking part in the analysis. Reporting errors occur when an individual fails to report a sibling's death, misreports the age of a sibling, or does not recall the exact date when a sibling died.
Why Was This Study Done?
This study was conducted to estimate whether modifying a standard siblings' survival history questionnaire could improve the accuracy of data obtained. The researchers conducted a study in Niakhar, Senegal, using a modified siblings' survival history questionnaire to incorporate some innovative techniques for assisting memory recall, such as recall cues, to help prevent omissions. The researchers also introduced an event history calendar format to help with more accurate reporting of dates. This modified questionnaire is called the siblings' survival calendar.
What Did the Researchers Do and Find?
The researchers randomly assigned men and women registered by the Niakhar Health and Demographic Surveillance System, aged 15–59 years old, to an interview with the basic questionnaire or the modified siblings' survival calendar. The modifications included emphasizing the importance of accurate recall before the participant started and asking respondents to list their maternal siblings in the order that they came to the mind instead of birth order. Also, the researchers used supplementary interviewing techniques designed to stimulate the recall of potentially omitted siblings and also used an event history calendar approach for collecting data on ages at, and dates of, vital events that had affected the siblings of a respondent.
The researchers compared the results from the two survey instruments and precise data on adult mortality collected by continuous demographic surveillance in a small area of Senegal. They found that the calendar survey improved the sensitivity of survey data in recording adult female deaths. In addition, the modified questionnaire significantly reduced age and date heaping (the tendency of respondents to round off dates) observed with the basic questionnaire. The modified questionnaire took six minutes longer to complete on average than the basic questionnaire.
What Do These Findings Mean?
These findings suggest that a new approach (the siblings' survival calendar) that uses simple interview tools to improve estimates of mortality in resource-limited countries is feasible and may improve the quality of the data from siblings' survival histories, particularly in reporting female deaths. Although the study was limited by sample selectivity, limited external validity, and multiple testing, the findings suggest that this new approach has the potential to allow the collection of more accurate data from siblings' survival histories than that collected from the current questionnaire. The next step is to validate these findings in other settings.
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001652.
The World Health Organization Regional Office for Africa has a page on vital statistics
Information on demographic data available in Senegal can be accessed on the website of the Agence Nationale de la Statistique et de la Démographie (in French)
The UN Statistics Division has a page on their vital registration and vital statistics coverage assessment
The World Mortality Report 2013 presents the latest mortality estimates developed by the Population Division of the United Nations, including the probability of dying between the ages of 15 and 60 years
The Institute for Health Metrics and Evaluation has developed a visualization tool that allows one to see how siblings' survival histories are adjusted to generate estimates of adult mortality
More information on Health and Demographic Surveys surveillance in Niakhar, Senegal, is available (in French) on the website of the Institut de Recherche pour le Développement