India - Unorganised Manufacturing Enterprises Survey [AREA Frame] : NSS 62nd Round : July 2005 - June 2006

Outline of sample design: Two frames were used for the 62nd round survey viz. List frame and Area frame.

List frame:

This was used only for urban sector and that too for selection of manufacturing enterprises only. For unorganised manufacturing enterprises, a list of about 8000 big non-ASI manufacturing units in the urban sector prepared on the basis of the data of the census of manufacturing enterprises conducted by Development Commissioners of Small Scale Industries (DCSSI) in 2003 was used as list frame.

The 'big' DCSSI units in the urban sector had been identified by the criteria given below:
(1) From the list of registered SSI units, units not registered under sections 2m(i) or 2m(ii) of Factories Act, 1948 and belonging to NIC '98 codes 01405, 15 - 37 were considered.
(2) Out of the above units, the units whose gross value of output in 2001 were more than 6 times the average output (Rs. 14,32,314) of all urban SSI units were separated out.
(3) From the above units, those with 6 or more workers were identified as the big units for list frame. About 8000 such units constituted the list frame.
All these units in the list frame were to be surveyed and there was not any sampling for list frame. To avoid duplication, these units were excluded from the list of enterprises prepared in the selected urban blocks/villages drawn from the area frame. There was no sub-round restriction for the list frame units.
All the enterprises in the list frame are common to both central and state samples.

Area Frame:

In the area frame approach, the list of all the villages (panchayat wards in case of Kerala) / urban blocks of the country served as the sampling frame of FSUs. The first stage units (FSUs) were villages (panchayat wards in case of Kerala) in the rural sector and urban blocks in the urban sector. The ultimate stage units were unorganised manufacturing enterprises in both the sectors. However, in case of
large FSUs requiring hamlet-group (hg) / sub-block (sb) formation, one intermediate stage in the sampling involved the selection of two hg's / sb's from each FSU out of a minimum of three hg's/sb's formed in the FSU. Of these two selected hg's/sb's, one was selected with probability '1' (termed as segment 1) and another one (termed as segment 2) was selected from among the remaining hg's/sb's of the FSU at random. The hg/sb selected with certainty (i.e. segment 1) was the hg/sb having maximum number of directory manufacturing establishments (DMEs) (or with maximum number of non-directory manufacturing establishments (NDMEs) if there was no DME, or with
maximum number of own account manufacturing enterprises (OAMEs) if there was no DME/NDME, or with maximum population if there was no DME/NDME/OAME4 in the entire FSU). Smaller FSUs without any hg/sb formation were identified/categorized as segment 1 for the purpose of survey (segment 2 does not exist for such FSUs). As regards the first stage stratification, two basic strata were formed within each district of a State/UT: rural stratum comprising all rural areas of the district and urban stratum consisting of all urban areas of the district. However, each city with a population of one million or more as per Census 2001 was invariably treated as a separate stratum by itself. For details of stratification, sub-stratification and selection of sample FSUs, reference
may be made to estimation procedure document.

For each of segments 1 and 2 of the selected sample FSUs, a frame of eligible manufacturing enterprises was prepared by the field investigators by visiting each every house/household within the selected geographical area. While doing so, if any enterprise of the list frame was encountered, care was taken not to list it again within segment 1 or 2 as a part of the area sample / area frame to guard against duplication of enterprises between the two types of frames. Listing and sampling of enterprises in the area frame was ndependent for each of segments 1 and 2. In this context, it may be mentioned that for each selected FSU of rural sub-strata 1 and 2
only, segment 9 was also carved out within the FSU, which comprised top 10 big non-ASI registered SSI manufacturing units
located within the boundaries of the entire FSU. The list of such units for selected FSUs was made available to the field investigators in order to facilitate formation of segment 9. Respective frames of segments 1 and 2 in these FSUs excluded the units listed under
segment 9.

All the eligible enterprises listed under each of segments 1, 2 and 9 were stratified into 2 broad second-stage strata by enterprise type i.e. OAME & NDME/DME. Each of these two broad second-stage strata was further divided into 3 broad manufacturing groups (BMG) i.e. BMG 1, BMG 2 and BMG 3. BMG 1 comprised eligible enterprises belonging to NIC codes 15 and 20. BMG 2 consisted of eligible enterprises belonging to NIC Codes 23, 27, 30-35 and 01405 while all other eligible enterprises belonging to the rest of the NIC codes under coverage formed BMG 3. Thus within a segment for any given sample FSU, six ultimate second-stage strata were formed by jointly considering the broad second-stage strata and BMG. A total of 12 manufacturing enterprises - two from each ultimate second-stage stratum - were selected for detailed enquiry. In case of shortfall of enterprises in the frame of any particular second-stage stratum, compensation was made by selecting additional samples from other second-stage strata so that a total of 12 enterprises were selected from each FSU for detailed enquiry.

Design-based estimates of aggregates for any selected survey characteristic were obtained separately for list frame and area frame. Finally these two sets of estimates were added to get the pooled aggregate estimate for the combined frame. In this report,
discussion will be focused on the pooled estimate based on two types of frames used in the survey.


There was no deviation from the original sample deviation.


Out of 8,000 enterprises selected from the list frame, data could be collected from only 2,260 enterprises Thus a large percentage (72%) of the list frame enterprises became casualties. Among the enterprises which were treated as casualties, the majority (around 70%) actually belonged to the category of “Government/public sector undertaking/ASI units”, which were not under the coverage of 62nd round. Another 18% of the enterprises were found to be either non-operative or not traceable.

In the area frame, 80,637 enterprises (42,050 from rural India and 38,587 from urban India) spread over 4,798 villages and 5,125 urban blocks across the country were surveyed. It is worthwhile to mention here that even though a large percentage of list frame enterprises were not surveyed, theoretically the surveyed enterprises netted through the list frame and area frame represented the whole universe of
the unorganised manufacturing sector.

Thus, altogether a total of 82,897 unorganised manufacturing enterprises considering both list frame and area frame were surveyed.


Weights (or multipliers) are given at the end of each record. Wgt_ss is the variable for sub-sample-wise estimates and Wgt_combined for combined sub-sample estimates.

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

For generating subsample-combined estimates based on data of all subrounds taken together all enterprises are to be considered.