Characteristics of Households - Childinfo.org

Appendix A Sample Design for the Serbia SampleThe major features of the sample design are describedin this appendix. Sample design features includethe target sample size, sample allocation, samplingframe and listing, choice of domains, sampling stages,stratification, and the calculation of sample weights.The primary objective of the sample design for theSerbia Multiple Indicator Cluster Survey was to producestatistically reliable estimates of most indicators, at thenational level, and for 4 regions: Belgrade, Vojvodina,Sumadija and Western Serbia and Southern and EasternSerbia, for urban and rural areas, of the country.A stratified, two-stage random sampling approach wasused for the selection of the survey sample.Sample Size and Sample AllocationThe target sample size for the Serbia MICS4 wascalculated as 6800 households and 400 enumerationareas, considering the proposed formula and budgetavailable. For the calculation of the sample size, the keyindicator used was the percentage of children aged 0–4years who had had Acute Respiratory infections. Thefollowing formula was used to estimate the requiredsample size for this indicator:wherenn = [4(r)(1– )(1–r)(f)(1.15)][(0.12r) 2 (p)(ñ)])]is the required sample size, expressed as thenumber of households4 is a factor to achieve the 95 percent level ofconfidenceris the predicted or anticipated value of the indicator,expressed in the form of a proportion1.15 is the factor necessary to raise the sample size by 15per cent for the expected non-responsefis the shortened symbol for deff (design effect)0.12r is the margin of error to be tolerated at the 95percent level of confidence, defined as 12 per centof r (relative margin of error of r)pis the proportion of the total population upon whichthe indicator, r, , is basedñis the average household size (number of personsper household).For the calculation, r (percentage of children aged 0–4 yearswho had had Acute Respiratory infections) was assumed tobe 12 percent. The value of deff (design effect) was taken as1.5 based on estimates from previous surveys, p (percentageof children aged 0–4 years in the total population) wastaken as 5.1 percent, ñ (average household size) was taken as3, and the response rate is assumed to be 85%.The resulting number of households from this exercise wasabout 23000 households, which is the sample size neededto provide a large number of children under 5 (about 3500)for drawing reliable conclusions. Therefore, in order toreduce the number of households in the sample, but not tolose estimation reliability, the stratification of the sampleinto categories with and without children aged 0–4 yearswas needed. The required number of households in eachcategory was obtained supposing an overall sample of 6800households, 400 clusters and same number of householdswith children under 5 per cluster. Assuming one childunder 5 per household and considering the requirednumber of sample children, the total sample size wascalculated as 3600 (9 per cluster) households with childrenunder 5 and 3200 (8 per cluster) of households withoutchildren under 5. Thus, the overall number of householdsto be selected per cluster was determined as 17 households.The final target number of sample households withchildren per cluster was increased to 10 (12 for Belgraderegion) in order to compensate for sample clusters with lesshouseholds with children found in the listing.Stratification of enumeration areas for Serbia was doneaccording to type of settlement (urban and rural), and 25Areas (Belgrade, West Bačka, South Banat, South Bačka,North Banat, North Bačka, Central Banat, Srem, Zlatibor,MONITORING THE SITUATION OF CHILDREN AND WOMEN 257