India - Survey on Morbidity and Health Care January - June 2004, NSS 60th Round

An outline of the sampling design: The sampling design adopted for the survey was essentially a stratified multi-stage one for both rural and urban areas. The first stage units (FSUs) were villages (panchayat wards for Kerala) for rural areas and NSS Urban Frame Survey (UFS) blocks for urban areas. The ultimate stage units (USUs) were households. Large FSUs were subdivided into hamlet-groups (rural)/sub-blocks (urban). Details of the formation of hamlet-groups/sub-blocks and procedure of selection of hamlet-groups/sub-blocks and then of households are also given in Appendix B.

Sampling Frame for FSUs: The list of villages (panchayat wards for Kerala) as per 1991 Census and latest lists of UFS blocks of NSSO were respectively used for selection of rural and urban sample FSUs. For selection of sample villages from the State of Jammu & Kashmir, the list of villages as per 1981 Census was used as the sampling frame. However, interior villages of Nagaland situated beyond 5 kms. of the bus route and inaccessible villages of Andaman & Nicobar Islands were left out of the survey coverage of NSS 60th round.

Stratification : Rural sector: Two special strata will be formed at the State/ UT level, viz.
Stratum 1: All FSUs with population between 0 to 50 and
Stratum 2: FSUs with population more than 15,000.
Special stratum 1 will be formed if at least 50 such FSUs are found in a State/UT.
Similarly, special stratum 2 will be formed if at least 4 such FSUs are found in a State/UT.Otherwise, such FSUs will be merged with the general strata.

Urban sector: In the urban sector, strata will be formed within each NSS region on the basis of size class of towns as per Population Census 2001. The stratum numbers and their composition (within each region) are given below.
stratum 1 : all towns with population less than 50,000
stratum 2 : all towns with population 50,000 or more but less than 2 lakhs
stratum 3 : all towns with population 2 lakhs or more but less than 10 lakhs
stratum 4, 5, 6,...: each town with population 10 lakhs or more.The stratum numbers will remain as above even if, in some regions, some of the strata are not formed.

Total sample size (FSUs): 7612 FSUs have been allocated at all-India level on the basis of investigator strength in different States/UTs for central sample and 8260 for state sample.

Allocation of total sample to States and UTs: The total number of sample FSUs is allocated to the States and UTs in proportion to provisional population as per Census 2001 subject to the availability of investigators ensuring more or less uniform work-load.

Selection of FSUs: FSUs will be selected with Probability Proportional to Size With Replacement (PPSWR), size being the population as per Population Census 1991 in all the strata for rural sector except for stratum 1. In stratum 1 of rural sector and in all the strata of urban sector, selection will be done using Simple Random Sampling Without Replacement (SRSWOR). Within each stratum, samples will be drawn in the form of two independent subsamples in both the rural and urban sectors.


Allocation of State/UT level sample to rural and urban sectors: State/UT level sample is allocated between two sectors in proportion to provisional population as per Census 2001 with 1.5 weightage to urban sector subject to the restriction that urban sample size for bigger states like Maharashtra, Tamil Nadu etc. should not exceed the rural sample size. Earlier practice of giving double weightage to urban sector has been modified considering the fact that there has been considerable growth in urban population. A minimum of 8 FSUs will be allocated to each state/UT separately for rural and urban areas.

The procedure for selection of fsus/usus is given in detail in Appendix B of the report no.507 attached as external resources.


There was no deviation from the original sample deviation.


Sample size -- first-stage units: In all, 10,072 villages were planned to be surveyed in this round. Of these, 4,908 were allocated to the central sample -- the part surveyed mainly by the NSSO field staff -- and the rest to the State sample -- the part surveyed by the State agencies. In the urban sector, the allocations for the Central and State samples were, respectively, 2,708 and 3,096 blocks. This report is based on the estimates obtained from the central sample alone. The number of villages and that of urban blocks actually surveyed as the central sample were 4,755 and 2,668 respectively. 1.7.3 Sample size -- second-stage units: For Schedule 25.0, 10 households were planned to be surveyed in each selected FSU. In the Central sample, the actual numbers of households surveyed in the rural and urban areas were 47,302 and 26,566, respectively.


For generating any estimate, one has to extract relevant portion of the data, and aggregate after applying the weights.

Weights (or multipliers) VARIABLES are given at the end of record of each dataset. The weights (multipliers) are
WGT_SS for Sub-sample-wise estimation and WGT_Combined for combined subsample estimates.

All records of a household will have same weight figure. In case of those Blocks/Levels, where Item/Person Sl.No. is not applicable the field is filled up with 00000.

Use of subsample-wise weights (multipliers)

For generating subsample-wise estimates based on data of all subrounds taken together, either Subsample-1 households or Subsample-2 households are to be considered at one time. Subsample code is available in the dataset For generating subsample-combined estimates based on data of all subrounds taken together all households are to be considered.