Abstract

On 17 December 2015, the General Director of General Statistic Office issued Decision No 1160/QD-TCTK on the 2016 Labour Force survey, along with its survey plan. The purpose of the survey was to collect the information on 2016 labor market participation from those people who are 15 years old and above currently residing in Vietnam; regarded as a basic for aggregating and compiling national statistical indicators on labor, employment, unemployment and income. These results would support for ministries and branches assessing and comparing the changes in labour market among quarters within the reference year as well as with those of previous annual labour force surveys conducted by GSO. These results would be also considered as a basic to develop and plan policies on human resource development; activities of investment, production and business accordant with the development trend on labor market; as well as to access and apply International Labor Organization’s updated recommendations on labor and employment, especially in term of “labor under-utilization” into the reality of Vietnam. The statistics would be aggregated quarterly for the national and regional levels; and yearly for the provincial level.

Geographic coverage

Whole country.

Analysis unit

• Households
• Individuals ages 15 and above

Universe

Population ages 15 and over (working age population).

Kind of data

Sample survey data [ssd]

Sampling procedure

Sampling frame The sample of 2016 Labor Force Survey is the 2 stage stratified sample in order to ensure the presentative of quarterly aggregated statistics for the whole country, urban/rural, 6 social economic regions, Hanoi and Hochiminh cities as well as annually aggregated ones for 63 provinces/cities. Each province/city would constitute a main stratum with two sub-stratums namely urban and rural ones. The sampling frame is based on the 2015 Inter-censal Population and Housing Survey's selected enumeration areas.

Sample size The 2016 Labor Force Survey was conducted with the sample size of 50.640 households/quarter, (that is, equivalent to 16.880 households/month). The sample size was designed and allocated to ensure the statistical significance/ preventative of quarterly aggregated statistics at regional level and annually aggregated ones at provincial level.

Sampling deviation

The sample of this survey is stratified into 2 stages and designed as follows:

• Stage 1 (selecting EAs): Each province/city will constitute a main stratum divided into 2 sub stratums (of which, one will be representative for urban areas and the other is for rural areas). At this stage, list of provincial enumeration areas (the master sample frame – taken from the 1/4/2014 Inter-censal Population and Housing Survey’s 20% sample) will be divided into 2 independent sub-sample frames (urban and rural), and EAs will be selected by the method of probability proportional to size - PPS.

• Stage 2 (selecting households): At each selected EA (that is determined in stage 1), after updating the EA and making the list of households, the updated list of households will be divided into 2 groups (defined as the upper/first and the lower/ second half of the list of households). Then, at each half, 15 households will be selected systematically.

In order to improve the design efficiency and ensure to the reliability of survey sample, the sample will be selected alternately (under the 2-2-2 rotation). By this way, each EA will be divided into 02 rotational groups, whose households will be selected into sample in two adjacent quarters, and then excluded in 2 succeeding adjacent quarters, finally selected again into the sample in 2 following adjacent quarters. Each EA will be selected into the sample 4 times during a year at most.

Mode of data collection

Face-to-face [f2f]

Research instrument

Single questionnaire covering: - Household characteristcs - Individual characterists for those ages 15 and over as well as information on economic activity or inactivity

Response rate

Residence/Socio-economic region Total Male Female Labor force participation rate Entire country 100.0 100.0 100.0 77.5 Urban 31.9 32.0 31.9 71.0 Rural 68.1 68.0 68.1 81.0

This layer shows which parts of the United States and Puerto Rico fall within ten minutes' walk of one or more grocery stores. It is estimated that 20% of U.S. population live within a 10 minute walk of a grocery store, and 92% of the population live within a 10 minute drive of a grocery store. The layer is suitable for looking at access at a neighborhood scale.When you add this layer to your web map, along with the drivable access layer and the SafeGraph grocery store layer, it becomes easier to spot grocery stores that sit within a highly populated area, and grocery stores that sit in a shopping center far away from populated areas. Add the Census block points layer to show a popup with the count of stores within 10 minutes' walk and drive. This view of a city begins to hint at the question: how many people have each type of access to grocery stores? And, what if they are unable to walk a mile regularly, or don't own a car?How to Use This Layer in a Web MapUse this layer in a web map to introduce the concepts of access to grocery stores in your city or town. This is the kind of map where people will want to look up their home or work address to validate what the map is saying. See this example web map which you can use in your projects, storymaps, apps and dashboards.The layer was built with that use in mind. Many maps of access use straight-line, as-the-crow-flies distance, which ignores real-world barriers to walkability like rivers, lakes, interstates and other characteristics of the built environment. Block analysis using a network data set and Origin-Destination analysis factors these barriers in, resulting in a more realistic depiction of access.Lastly, this layer can serve as backdrop to other community resources, like food banks, farmers markets (example), and transit (example). Add a transit layer to immediately gauge its impact on the population's grocery access. You can also use this map to see how it relates to communities of concern. Add a layer of any block group or tract demographics, such as Percent Senior Population (examples), or Percent of Households with Access to 0 Vehicles (examples).The layer is a useful visual resource for helping community leaders, business and government leaders see their town from the perspective of its residents, and begin asking questions about how their community could be improved.Data sourcesPopulation data is from the 2010 U.S. Census blocks. Each census block has a count of stores within a 10 minute walk, and a count of stores within a ten minute drive. Census blocks known to be unpopulated are given a score of 0. The layer is available as a hosted feature layer.Grocery store locations are from SafeGraph, reflecting what was in the data as of October 2020. Access to the layer was obtained from the SafeGraph offering in ArcGIS Marketplace. For this project, ArcGIS StreetMap Premium was used for the street network in the origin-destination analysis work, because it already has the necessary attributes on each street segment to identify which streets are considered walkable, and supports a wide variety of driving parameters.The walkable access layer and drivable access layers are rasters, whose colors were chosen to allow the drivable access layer to serve as backdrop to the walkable access layer. Alternative versions of these layers are available. These pairs use different colors but are otherwise identical in content.Data PreparationArcGIS Network Analyst was used to set up a network street layer for analysis. ArcGIS StreetMap Premium was installed to a local hard drive and selected in the Origin-Destination workflow as the network data source. This allows the origins (Census block centroids) and destinations (SafeGraph grocery stores) to be connected to that network, to allow origin-destination analysis.The Census blocks layer contains the centroid of each Census block. The data allows a simple popup to be created. This layer's block figures can be summarized further, to tract, county and state levels.The SafeGraph grocery store locations were created by querying the SafeGraph source layer based on primary NAICS code. After connecting to the layer in ArcGIS Pro, a definition query was set to only show records with NAICS code 445110 as an initial screening. The layer was exported to a local disk drive for further definition query refinement, to eliminate any records that were obviously not grocery stores. The final layer used in the analysis had approximately 53,600 records. In this map, this layer is included as a vector tile layer.MethodologyEvery census block in the U.S. was assigned two access scores, whose numbers are simply how many grocery stores are within a 10 minute walk and a 10 minute drive of that census block. Every census block has a score of 0 (no stores), 1, 2 or more stores. The count of accessible stores was determined using Origin-Destination Analysis in ArcGIS Network Analyst, in ArcGIS Pro. A set of Tools in this ArcGIS Pro package allow a similar analysis to be conducted for any city or other area. The Tools step through the data prep and analysis steps. Download the Pro package, open it and substitute your own layers for Origins and Destinations. Parcel centroids are a suggested option for Origins, for example. Origin-Destination analysis was configured, using ArcGIS StreetMap Premium as the network data source. Census block centroids with population greater than zero were used as the Origins, and grocery store locations were used as the Destinations. A cutoff of 10 minutes was used with the Walk Time option. Only one restriction was applied to the street network: Walkable, which means Interstates and other non-walkable street segments were treated appropriately. You see the results in the map: wherever freeway overpasses and underpasses are present near a grocery store, the walkable area extends across/through that pass, but not along the freeway.A cutoff of 10 minutes was used with the Drive Time option. The default restrictions were applied to the street network, which means a typical vehicle's access to all types of roads was factored in.The results for each analysis were captured in the Lines layer, which shows which origins are within the cutoff of each destination over the street network, given the assumptions about that network (walking, or driving a vehicle).The Lines layer was then summarized by census block ID to capture the Maximum value of the Destination_Rank field. A census block within 10 minutes of 3 stores would have 3 records in the Lines layer, but only one value in the summarized table, with a MAX_Destination_Rank field value of 3. This is the number of stores accessible to that census block in the 10 minutes measured, for walking and driving. These data were joined to the block centroids layer and given unique names. At this point, all blocks with zero population or null values in the MAX_Destination_Rank fields were given a store count of 0, to help the next step.Walkable and Drivable areas are calculated into a raster layer, using Nearest Neighbor geoprocessing tool on the count of stores within a 10 minute walk, and a count of stores within a ten minute drive, respectively. This tool uses a 200 meter grid and interpolates the values between each census block. A census tracts layer containing all water polygons "erased" from the census tract boundaries was used as an environment setting, to help constrain interpolation into/across bodies of water. The same layer use used to "shoreline" the Nearest Neighbor results, to eliminate any interpolation into the ocean or Great Lakes. This helped but was not perfect.Notes and LimitationsThe map provides a baseline for discussing access to grocery stores in a city. It does not presume local population has the desire or means to walk or drive to obtain groceries. It does not take elevation gain or loss into account. It does not factor time of day nor weather, seasons, or other variables that affect a person's commute choices. Walking and driving are just two ways people get to a grocery store. Some people ride a bike, others take public transit, have groceries delivered, or rely on a friend with a vehicle. Thank you to Melinda Morang on the Network Analyst team for guidance and suggestions at key moments along the way; to Emily Meriam for reviewing the previous version of this map and creating new color palettes and marker symbols specific to this project. Additional ReadingThe methods by which access to food is measured and reported have improved in the past decade or so, as has the uses of such measurements. Some relevant papers and articles are provided below as a starting point.Measuring Food Insecurity Using the Food Abundance Index: Implications for Economic, Health and Social Well-BeingHow to Identify Food Deserts: Measuring Physical and Economic Access to Supermarkets in King County, WashingtonAccess to Affordable and Nutritious Food: Measuring and Understanding Food Deserts and Their ConsequencesDifferent Measures of Food Access Inform Different SolutionsThe time cost of access to food – Distance to the grocery store as measured in minutes