National Sample Survey Office under Ministry of Statistics and Programme Implementation conducts large scale surveys on various Socio- Economic subjects to facilitate policy formulation in the country. Urban Frame Survey provides frame for sample selection for such surveys in urban areas.
A sampling frame is an essential pre-requisite for organizing and conducting any sample survey. Updatedness, completeness and fairly accurate information of sampling units leading to identifiability are the essential features of a usable frame.
In practice, however, it is extremely difficult to get a fairly satisfactory frame. On such occasions, it is customary to make special efforts to build up a sampling frame to meet the specific requirements. Field Operations Division (FOD) of National Sample Survey Office (NSSO) does similar exercise through Urban Frame Survey to prepare the frame for Socio- Economic surveys.
A household approach is adopted for collecting data through most socio-economic inquiries. Since the frame for ultimate sampling units (households) is neither available nor feasible to be prepared afresh every time on account of time and cost factors, the sampling methods are so designed as to select the households in successive stages. For the rural areas, list of census villages comes in handy as an operationally convenient and readily accessible frame of first stage units. In the urban sector, however, the population census does not provide an analogous list of geographical units that could be conveniently adopted as a sampling frame. The UFS was conceived and formulated to obviate this particular situation.
Each UFS block has been envisaged to be a compact areal unit consisting of 80-200 households in general and the block is bounded by well-defined, clear-cut and natural / permanent boundaries. The blocks are mutually exclusive and exhaustive so that the blocks carved out in any given town add up to the total area of the town. The blocks are so formed that they depict permanent landmarks and corner points; they are distinguishable from one another; and, are identifiable over time. While town is a big areal entity, UFS block is a small areal unit. Striking a compromise between the two, the concept of Investigator Unit has been evolved in the UFS. Investigator Unit (IV Unit) is a well-defined and clearly demarcated geographical area consisting of about 20 to 50 blocks. IV Unit maps are drawn in standard-sized map sheets.
During the last UFS Phase (2007-12) a survey of more than 7000 towns including newly declared Census towns involving updation/formation of more than 6 lakhs UFS blocks was undertaken. Ladakh region of Jammu & Kashmir state was brought under the coverage of UFS and formation of blocks in Leh and Kargil towns was carried out for the first time in the history of NSSO which would pave way for future surveys in the region.
The current UFS Phase 2012-17 has been initiated for updation of UFS blocks. All the IV units and UFS maps of last phase have been electronically stored and linkage of the details of blocks with the maps made. UFS maps and records on demand are supplied to Government department free of cost and to the private institution and research scholars as per the laid down procedure.