A grid-based sample design framework for household surveys using the WorldPop dataset was conducted in DRC and a nonparametric estimator was applied to evaluate the sample design and determine sample size estimation. used LandScan to generate 1 × sampling units with probability proportional to size (PPS) and selected one household in one building and performed a random walk. In practice, only two gridded population datasets have been used for household survey sampling: LandScan and WorldPop. Similarly, being able to identify areas which have seen a net decrease in population can also increase the efficiency over an outdated census.
DEFINE THE GRIDDED REFERENCE GUIDE GRG UPDATE
Because of this property, gridded population estimates can be useful for survey sample design even when a census frame exists because it can be used to update older census datasets, subdividing EAs that have grown too large. From a sample design efficiency perspective, similar population estimates in the Primary Sampling Unit (PSU)-which are the grid cell and EA, respectively-equally sized population leads to greater precision in the resulting estimates. įrom a survey practitioner perspective, a key difference between gridded population data and census data is that grid cells are uniform in size but variable in population totals whereas census EAs vary in size but have similar population totals. Several gridded population datasets with different spatial resolutions are available in LMICs including WorldPop, Gridded Population of the World (GPWv4), Global Human Settlement Population Grid (GHS-POP), High-Resolution Settlement Layer (HRSL), Global Rural–Urban Mapping Project (GRUMP), LandScan, and Demobase Population datasets. Currently available gridded population datasets are derived with models that either disaggregate census data or predict population density based on a subset of the population, and can incorporate information from spatial covariates, such as land cover type, road infrastructure, nightlight intensity and settlement areas. Gridded population data are usually produced by models to give estimate counts of population density in uniform grid cells.
DEFINE THE GRIDDED REFERENCE GUIDE GRG FULL
Where full census data are not available in a country, gridded population datasets have emerged over the last decade as a potential alternative to building household survey sampling frames. For example, Afghanistan has not conducted a full national census since 1979, and Somalia since 1987. However, the use of census data as the sampling frame is problematic in many countries around the world, particularly in LMICs, since their census data are often outdated, incomplete, or missing, or inaccessible.
The sampling frame also represents the best-known distribution of the population at the time of the sample selection, making it a critical input to the weight calculations. The use of census data as a source of the sampling frame is critical as it allows survey designers to efficiently allocate their sample across areas or populations as well as identify groups typically under-represented or rare. Household surveys typically rely on census data as a sampling frame. In low- and middle-income countries (LMICs), surveys such as the Living Standard Measurement Surveys (LSMS), the UN’s Multiple Indicator Cluster Survey (MICS) and the Demographic and Health Surveys (DHS) have been routinely implemented since the 1980s. In particular, household surveys are the main means of providing detailed health/socio-economic information in a timely fashion, since the burden of conducting of the full census is labor and cost-prohibitive. In all countries, surveys and census data are the main source of demographic, health and socio-economic data. The Creative Commons Public Domain Dedication waiver ( ) applies to the data made available in this article, unless otherwise stated in a credit line to the data. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material.
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