Sampling Methodology of PLFS
Sampling Methodology of PLFS
The sampling design of Periodic Labour Force Survey (PLFS) has been revamped from January 2025 to address the requirement of high frequency labour market indicators with enhanced coverage from PLFS. The revamped PLFS is envisaged to address the following objectives:
Usual Status (ps+ss) and Current Weekly Status (CWS) refers to frameworks for determining activity status of person surveyed based on reference periods of last 365 days and last seven days preceding the date of survey, respectively.
Salient aspects of the change in the sampling methodology of PLFS are given below:
Enhancement of the sample size
The revamped PLFS sample design is a multistage stratified design. List of census 2011 villages / urban Frame Survey (UFS) blocks / sub-units (for those villages or UFS blocks where sub-units are formed within) together formed the sampling frame for selection of the First Stage Units (FSUs). In the revamped PLFS sample design, a total sample size of 22,692 FSUs is planned to be surveyed (12,504 FSUs in the rural areas and 10,188 in the urban areas) in each year of the two-year panel with first visit schedule as compared to 12,800 FSUs surveyed in PLFS upto December, 2024.
A total of 12 households will be surveyed from each of the selected FSUs which implies an overall sample size of around (22,692 x 12) = 2,72,304 households. This marks a 2.65 time increase in sample households to be covered in PLFS as compared to the number of sample households covered upto December, 2024 (which was around 1,02,400). The enhanced sample size is expected to provide reliable estimates of labour market indicators with improved precision.
Changes in the Rotation panel scheme
In the rotational panel scheme adopted in the revamped PLFS sample design employed from January 2025, each selected household is visited four times in four consecutive months –in the beginning with first visit schedule in the first month and other three with the revisit schedule in the following three months for both rural and urban areas. This rotational panel scheme ensures a 75% matching of the samples surveyed between two consecutive months for both rural and urban areas and 50% matching in successive quarters.
Changes in the First (or Primary) Stage sampling units (FSUs) of the multistage design
With a view to ensure uniformity in the size of First Stage Units and for operational convenience, large census 2011 villages and UFS blocks are notionally divided into smaller units of more or less equal size, known as sub-units depending on a pre-defined criteria based on population in the village or number of households in the UFS block.
In the revamped PLFS design employed from January 2025, the list of census 2011 villages / sub-units (for those census 2011 villages where sub-units are formed within) together formed the sampling frame for selection of the First Stage Units for rural areas.
Likewise, the list of latest available UFS blocks / subunits (for those UFS blocks where sub-units are formed within) together formed the sampling frame for selection of the First Stage Units for urban areas.
Modification in the Stratification of First (or Primary) Stage sampling units
In the revamped PLFS sample design, district has been made the primary geographical unit, called basic stratum within a state/UT separately for rural and urban sectors for selecting FSUs for most part of the geography covered. In the remaining parts NSS region has been made the basic stratum.
Changes in selection scheme for selecting FSUs
In the revamped PLFS sample design, FSUs from each of the stratum / sub-strata is selected for each month following Simple Random Sampling (SRS) scheme.
The revamped PLFS sample design from January 2025 results in the following updation in the PLFS dissemination:
Availability of monthly estimates of key labour market indicators at the country level:
The revamped PLFS sample design will enable generation of the monthly estimates of key labour market indicators viz. Labour Force Participation Rate (LFPR), Worker Population Ratio (WPR) and Unemployment Rate (UR) at the all-India level following the Current Weekly Status (CWS) approach. The monthly estimates will help in timely policy interventions.
Extending quarterly estimates to rural areas:
Upto December, 2024 PLFS provided quarterly labour market indicators for the urban areas only. With the updation in the PLFS sample design quarterly estimates of employment unemployment indicators will be available for both rural and urban areas and hence for the entire country.
This information was given by the Minister of State (Independent Charge) of the Ministry of Statistics and Programme Implementation; Minister of State (Independent Charge) of the Ministry of Planning and Minister of State in the Ministry of Culture Rao Inderjit Singh in a written reply to a question in the Lok Sabha today.