Mongolia - MICS 2000

The principal objective of the sample design was to provide current and reliable estimates on a set of indicators covering the four major areas of the World Fit for Children declaration, including promoting healthy lives; providing quality education; protecting against abuse and combating HIV/AIDS. The population covered by the MICS - 2 is defined as the universe of all women aged 15-49 and all children aged under 5. A sample of households was selected and all women aged 15-49 identified as usual residents of these households were interviewed. In addition, the mother or the caretaker of all children aged under 5 who were usual residents of the household were also interviewed about the child.

The MICS - 2 collected data from a nationally representative sample of households, women and children. Sample design features include target sample size, sample allocation, sample frame and listing, choice of domains, sampling stages, stratification, and the calculation of sample weights.

The primary objective of the sample design for the Mongolia Multiple Indicator Cluster Survey was to produce statistically reliable estimates of most indicators, at the national level, for urban and rural areas, and for the five regions (Western, Khangai, Central, Eastern, Ulaanbaatar) of Mongolia. Urban and rural areas within regions were defined as the sampling domains.

A multi-stage, stratified cluster sampling approach was used for the selection of the survey sample.

Mongolia is divided into 6 regions. Each region is subdivided into provinces (aimags) and a capital city, and each province into soums, a capital city into districts, each soum into bags and each districts into khoroos.

The target sample size for the Mongolia MICS was calculated as 6000 households. For the calculation of the sample size, the key indicator used was the underweight prevalence among children aged 0-4 years. The average cluster size in the Mongolia MICS was determined as 20 households, based on a number of considerations, including the budget available, and the time that would be needed per team to complete one cluster. Dividing the total number of households by the number of households per cluster, it was calculated that the selection of a total number of 300 clusters would be needed in total. Proportional allocation of the total sample size (6000 households) to the five regions was performed.

In each region, the clusters (primary sampling units) were distributed to urban and rural domains, proportional to the size of urban and rural population in that region.

The administrative records of households and population, updated on an annual basis across the country, were used as the sampling frame for selection of clusters. The lowest administrative units (bagh and khoroo) were defined as primary sampling units (PSUs), and were selected from each of the sampling domains by using systematic pps (probability proportional to size) sampling procedures, based on the estimated sizes of the bagh and khoroos from the 2000 mid yearly administrative record. The first stage of sampling was thus completed by selecting the required number of units (bagh and khoroo) from each of the 6 regions.

Lists of households were prepared mostly by the officials of the bagh and khoroo. The households were then sequentially numbered from 1 to n (the total number of households in each bagh/khoroo) at the National Statistical Office, where selection of 20 households in each PSU was carried out using systematic selection procedures.

Details of sampling design of Mongolia MICS survey can be found in the Final Report of this survey.


No major deviations from the original sample design were made. All primary sampling units were accessed and successfully interviewed with good response rates.


6000 households were selected for the sample. Of these, 6000 were occupied households and 6000 were successfully interviewed for a response rate of 100%. Within these households, 8606 eligible women aged 15-49 were identified for interview, of which 8257 were successfully interviewed (response rate 95.9%), and 6199 children aged 0-5 were identified for whom the mother or caretaker was successfully interviewed for 6184 children (response rate 99.8%).


The Mongolia MICS survey sample is approximately self-weighting. Normalized (standardized) sample weights were calculated, however, to reflect differential response rates across sampling domains and small differences in sampling fractions across the domains.

The major component of the weight is the reciprocal of the sampling fraction employed in selecting the number of sample households in that particular sampling domain.

After the completion of fieldwork, response rates were calculated for each sampling domain. There were used to adjust the sample weights calculated for each cluster.

The adjustment for household non-response is equal to the inverse value of
RR = Number of interviewed households / Number of occupied households listed.

Similarly, the adjustment for non-response at the individual level (women aged 15-49 years and children aged under-five) is equal to the inverse value of
RR = Completed women's (or under-5's) questionnaires / Eligible women (or under-5s).

Numbers of eligible women and under-5 children were obtained from the household listing in the Household Questionnaire in households where interviews were completed.

The unadjusted weights for the households were calculated by multiplying the above factors for each PSU. There weights were then standardized (or normalized), one purpose of which is to make the sum of the interviewed sample units equal the total sample size at the national level. Normalization is performed by multiplying the aforementioned unadjusted weights by the ratio of the number of completed households to the total unadjusted weighted number of households. A similar standardization procedure was followed in obtaining standardized weights for the women's and under-5's questionnaires.