Sampling Procedure
Outline of Sample Design:
A stratified multi-stage design was adopted for the conduct of survey of NSS 47th round. The first-stage units were census villages (panchayat wards for Kerala) in the rural sector and the NSSO Urban Frame Survey (UFS) blocks in the urban sector. The ultimate stage units were households in both the sectors.
Sampling Frame for First-Stage Units:
For the rural sector, the list of Census 1991 villages (panchayat wards for Kerala) and Census 1981 villages for J & K constituted the sampling frame. For the urban sector, the list of latest available Urban Frame Survey (UFS) blocks was considered as the sampling frame.
Stratification
Rural sector:
Two special strata were formed as given below at the State/ UT level on the basis of Population Census 1991 viz.
Stratum 1: all FSUs with population between 0 to 50, and
Stratum 2: FSUs with population more than 15,000
The special stratum 1 was formed if at least 50 such FSU's were found in a State/UT. Similarly, special stratum 2 was formed if at least 4 such FSUs were found in a State/UT. Otherwise, such FSUs were merged with the general strata.
From the remaining FSUs (not covered under stratum 1 &2) general strata (hereafter, stratum will refer to general stratum unless otherwise mentioned) was formed and numbered 3, 4, 5 …. etc. (even if no special strata have been formed). Each district of a State/UT was normally treated as a separate stratum. However, if the provisional population of the district was greater than or equal to 2.5 million as per Census 2001, the district was divided into two or more strata with more or less equal population as per population census 1991 by grouping contiguous tehsils. However, in Gujarat, some districts were not wholly included in an NSS region. In such cases, the part of the district falling in an NSS region constituted a separate stratum.
Urban sector:
In the urban sector, stratum was formed within each NSS region on the basis of size class of towns as per Census 1991 town population except for towns specified in Table 4. The stratum number and their composition (within each region) are given below:
stratum 1: all towns with population (P) < 0.1 million
stratum 2: all towns with 0.1= P < 0.5 million
stratum 3: all towns with 0.5= P < 1 million
stratum 4,5,6, … each town with P= 1 million
Sample size: The total number of FSUs for the Survey of Disabled Persons was 6648 while the number fo SSUs was 56762.