Page 201 - Contributed Paper Session (CPS) - Volume 1

CPS1278 Desiree R. et al.
The proposed sampling design uses a stratified single-stage design with
the establishments treated as sampling units. The data used for this study is
the list of establishments from the 2018 Integrated Survey of Labor and
Employment (ISLE). Meanwhile, the 18 PSIC Sections were considered as the
primary strata or domains of the survey. For each domain, four strata were
formed which are defined in detail in Table 1.

Table 1. Characteristics of Strata and Sampling Strategies
Stratum Characteristic Sampling Strategy
0 Very small establishments whose aggregate TE Take none
contributes at most 5% of TE of all
establishments.
1 Smallest stratum formed by the LH algorithm Take none
2 Medium stratum formed by the LH algorithm Take none
3 Largest stratum formed by the LH algorithm Take all

For stratum 0, no establishments will be taken as these only contributes
very small amount to the overall total employment (TE) of the establishments.
Meanwhile, for strata 1, 2, and 3 the stratum boundaries will be obtained using
the LH algorithm.
The optimal sample size will also be obtained using LH algorithm for strata
2 and 3 while all establishments falling within the boundaries of stratum 3 will
be taken as samples.
As adapted from the 2011 Survey of Enterprises in the Philippines5, the
establishments were sorted according to their region and was followed by
systematic selection of samples in order to ensure that samples were
distributed across each region. This method would also induce implicit
stratification among the regions.
As the dataset used is a survey data, the method of obtaining samples
using LH was simulated for 200 times. This is to show that the CV for each of
the samples obtained using LH would approach the expected target CV.

3. Results
In order to obtain the optimal sample size and boundaries for each
stratum, cutoff sampling together with LH algorithm was applied. The resulting
sample size excludes the establishments whose aggregate TE contributes at
most 5% of TE for all establishments or those belonging to stratum 0. Hence,
the samples consist of establishments belonging to strata 1, 2 and 3 only. The
resulting sample size, the percentage of samples and the corresponding CV of
TE for each section is shown in Table 2. Meanwhile to further inspect the CV
of TE for the samples obtained, the CV for each subsection was obtained and
plotted per section as shown in Figure 1.

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