Sampling procedure
<p style="border:solid thin black;"> THE CLEANED AND HARMONIZED VERSION OF THE SURVEY DATA PRODUCED AND PUBLISHED BY THE ECONOMIC RESEARCH FORUM REPRESENTS 100% OF THE ORIGINAL SURVEY DATA COLLECTED BY THE CENTRAL AGENCY FOR PUBLIC MOBILIZATION AND STATISTICS (CAPMAS) </p>
---> Sample Design and Selection
At the beginning of the first quarter in 2018 (January-March),the sample design was developed. sample size was withdrawn 50% of the (panel households) visited in the same quarter last year and 50% of the sample size (new households) visited for the first time, as well as to divide the sample of each governorate into six parts instead of five , in addition to Develop research questions according to the goals of Nineteenth Congress of Labor Statistics held at Geneva in 2013, therefore new questions to measure informal employment and the informal sector. The coordination with all stages of the research process in parallel line. Starting from the stage of collecting data from the field, and sending the data using the tablet. In case of any errors, the forms are not accepted and sent to the researcher again for correction, such as the end of data collection and correcting them by returning to the family again and resending them, then the coding stage comes for each of the variables that need coding, which is (academic qualification -profession - economic activity).
The sample of Labor Force Survey is a two-stage stratified cluster sample and selfweighted to the extent practical.
The main elements of the sampling design are described as follows:
* Sample Size
Sample size designed for each quarter is 22500 households with a total of 90000 households per year (Designed Sample 90000, Implemented Sample 70113) , allocated 45.4% for Urban and 54.6 % for rural over all governorates ( urban / rural) in proportion to the size of each governorate , the sample divided to :
a. New Households with sample size 11502 households for each quarter.
b. Panel households with sample size 10998 households for each quarter selected from the same quarter in year 2019.
* Cluster size
The cluster size is 18 households.
* Sampling stages:
A- First sampling stage:
(1) Primary Sampling Unit:
The 2017 population census data was used to obtain an electronic list of areas of aid, or in other words, enumeration areas (EAS) with an average of 600-750 households through all the republic. This list represents the framework of the first phase of the sample, where 10,000 auxiliary areas were selected as primary sampling units (PSU) for the first phase of the main sample.
(2) Stratification and allocation of the initial inspection unit:
The governorate is considered the primary layer, which is divided into urban and rural as sub-classes, where the allocation commensurate with the size of the sample between governorates, and between urban and rural areas in each governorate in the first phase of inspection, in order to achieve selfweighting of the basic and sub-classes at the national level .
B- SECOND Sampling phase:
(1) The division of each initial survey into a number of parts approximately equal in size (200 households / part), each part is called an area plot.
(2) Selecting an area plot (one part of each primary sampling unit) using the simple random sampling method.
C- THIRD stage of Sampling:
1- The basic sample areas (10,000 area plots) were divided into four groups, each group contain 2,500 area plots) using the simple random sampling method, and one of the most important advantages of random division is that each area plot has the same opportunity to appear between the four groups.
2- Field work is carried out into four phases (each phase is executed every two years). The implementation of the first phase began since March 2018.
3- The goal of this subdivision is to ensure that the sample is not outdated for as long as possible, and that household data are constantly updated.
4- The representation of urban and rural areas at the level of the governorates of the Republic has been taken into account.
D- Sample Allocation among Governorates:
Governorate is considered the primary main strata that divided into substrata (Urban/ Rural), allocation proportional to size was determined among governorates as well as among urban and rural in each governorate at the first sampling stage.
Sample frame first Stage:
The Census lists of EA's for each strata constitute the frame of the sample first stage. The identification information appears on the EA's list includes District code,(Shiakha/Village)code, Census Supervisor and enumerator numbers, Census Supervisor number is unique at the level of (Shiakha /Village), while the enumerator number is unique within the EA enumeration assigned to supervisor. During investigating the list of EA's with regard to the number of households and their consistency with each EA, it has been found that number of households at these EA's are below the average ( less than 200 household ). The reason for that is that some enumerators included institutional households which have been excluded later and includes only households habiting in private housing. As a result, a decision was made to adjoin any EA with less than 160 H.H. to an adjacent one. Thus, in those exceptional cases the primary Sampling Units (PSU) consists of two EA's. To select the primary sampling units (Sampling first stage), the frame was arranged to provide implicit stratification with regard to the geographic location, where the urban of each governorate was arranged in a spiral according to the geographic location (kism / district). The same sort of ordering was made on the rural frame, but according to the district location. The systematic selection of EA's sample from such a sorted frame will ensure balanced distribution of the sample over the substrata of respective governorates, After this stage, the sample was selected with probability proportional to Size (PPS), of census households number in EA (200 households) was taken as a Measure of Size (MOS). The Sample households was selected from each EA using equal probability of the systematic selection method.
D- Division of Primary Sampling Unit:
Primary sampling unit (5000 EA) was divided into four rounds, each has (1250 EA). Then the household sample was then selected from each EA with equal probability, using the systematic selection method normally. The table (B) shows designed, implemented sample and Response Rate according to governorate (Urban & Rural).
A more detailed description of the different sampling stages and allocation of sample across governorates is provided in the Methodology document available among external resources in Arabic.