Data obtained from Demographic and Health Surveys (DHS) such as GDHSs are recognized for their accuracy and source of nationally representative information detailing the demographic and health status of developing countries like Ghana with much focus on young children and their mothers.
The four GDHSs used in this thesis contained good quality data on a number of child and maternal/household characteristics as well as data on geographic information. Data quality is of utmost importance to the DHS Program which is considered the gold standard for nationally representative data collection in developing countries (Kiersten, 2009). The following were some of the measures put in place to ensure data quality in the GDHSs: 1) field officers (interviewers, editors and supervisors) and data entry personnel are trained extensively on the survey instruments. The training which is
The structure of the data-sets
Survey years Number of clusters sampled Number of household sampled for interview Number of children <5 in households from which female
individuals were interviewed 1993 GDHS 400 Clusters 6,161 Households 2,204 Children 1998 GDHS 400 Clusters 6,375 Households 3,298 Children 2003 GDHS 412 Clusters 6,628 Households 3,844 Children 2008 GDHS 411 Clusters 11,913 Households 2,992 Children
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supported with interviewer and supervisor manuals involves classroom discussions and practice focusing on the three questionnaires (Household Questionnaire (HQ), Women’s Questionnaire (WQ) and Men’s Questionnaire (MQ)) based on model questionnaires developed by the MEASURE DHS programme; 2) Trainees selected as field editors and supervisors were given additional days of training on how to edit questionnaires and supervise fieldwork; 3) Training of interviewers was conducted mostly in English by senior staff from the Ghana Statistical Service (GSS) with technical support from ICF Macro; 4) A pre-test is conducted to test the survey instruments and to identify possible challenges ahead of the main survey; 5) Only female interviewers interviewed
respondents for the WQ and only male interviewers interviewed respondents for the MQ; 6) To reduce language barrier, the questionnaires were translated from English into three (3) major local languages, namely Ewe, Twi and Ga; 7) Interviewers were selected on the basis of in-class participation, field practice, fluency in the Ghanaian languages, and an assessment test. The most experienced trainees, those who had participated in the pre-test and those who did extremely well during the training were selected to be
supervisors and editors; 8) Senior staffs from GSS coordinated and supervised the field work whereas officials from ICF Macro participated in field supervision of interviews. The main reason for their visits is to check the quality of data being collected, ascertain whether the right procedures were being followed and assist in resolving any challenges that a team might be experiencing; 9) Completed questionnaires were returned
periodically from the field to the GSS office in Accra where they were entered and edited by data processing personnel specially trained for this task. The concurrent entry of the data gave the GSS the opportunity to advise field teams of problems detected during data entry which has an added advantage for data quality; 10) All data were entered twice for 100% verification (Ghana Statistical Service et al., 2009; Ghana
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Statistical Service et al., 2004; Ghana Statistical Service (GSS) and Macro International Inc (MI), 1994, 1999).
The GDHS collect information on similar variables in each survey iteration and these variables are named in the same way across all survey time periods. The GDHS also used the same survey methodology and were conducted by the same organization. In this thesis, we used data on children aged below 5 years with eligible anthropometric measurements (eg. weight and height) from the women’s questionnaire in each of the four GDHSs. We computed the weight-for-age, height-for-age and weight-for-height Z- scores using the 2006 World Health Organization growth standards and used these as measures of child’s nutritional outcomes in this thesis. The Z-scores used in the analysis are all within the plausible ranges and available for all children in this thesis.
All information on children in the GDHS data was reported by the mother apart from those that required measurement and test. For instance, information on child’s diarrhoea episodes is based on mother’s understanding of the signs and symptoms and this
understanding could vary from one mother to another or can differ across settings. This could introduce reporting bias. Also, it is difficult to directly measure household wealth status in Ghana. Because of this we used an asset-based index, which is generally considered a good proxy for household wealth status in developing countries. Another limitation of the data is incomplete information on child’s actual birthweight and as a result, the association between child’s nutritional outcomes and this variable could not be explored directly.
Furthermore, though complementary feeding is one of the key covariates to be
considered in our analysis, we were unable to explore the association between child’s nutritional outcomes and this variable in this study due to inadequate data on
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analysis but we did not pursue this because only 19% of children in the data-set had data on complementary feeding and this proportion could further reduce when other risk factors are accounted for should subsample analysis be considered. We hope future GDHSs will collect enough data on complementary feeding to allow the association between child’s nutritional outcomes and complementary feeding to be explored in further studies in this area.Other limitation includes the fact that some children in the GDHSs have unacceptable or biologically implausible Z-scores and could not be included in the analysis.