Data Collection and Analysis
In order to measure disparate impact, relevant demographic data for our projects and programs needs to be collected and analyzed to see if one protected class is disproportionately impacted compared to other groups. Please refer to Title VI – Types of Discrimination Factsheet for more information on disparate impact and its context within the Title VI program. This section will go over how to collect the data from the United States census, various ways to display and map that data, and how to do some basic entry level analysis of whether there is a disparate impact.
*** Disclaimer ***
This document is not intended as guidance, and it does not create new requirements or represent a statement of FHWA policy or interpretation of existing requirements. It is intended as an aid to recipients of federal financial assistance from the FHWA in the development of Title VI Plans, reviews, and other methods of administration. FHWA recipients should tailor their policies and procedures to suit their circumstances.
Please note that the U.S. Census will not provide Title VI demographic data for all situations. Some types of Title VI impacts—such as right of way/relocations and public involvement—will require Recipients to conduct surveys to collect demographic data from impacted persons. FHWA expects that recipients will make informed decisions on the appropriate sources of Title VI data. Recipients should contact their FHWA state division offices for any technical
U.S. Department of Justice (USDOJ) Title VI Website: The USDOJ coordinates Title VI compliance strategies and resources for all federal agencies. Its website contains useful information on Title VI.
USDOJ Title VI Legal Manual: This document is a comprehensive reference guide to Title VI caselaw and practice.
FHWA Civil Rights Office Census Add-On for Microsoft Excel
: FHWA Office of Civil Rights Census Add-On for Microsoft Excel – Excel add-in that will generate percentages and summarize the area under review after downloading census information. Instructions here.
Sources of Data - U.S. Census
The US Decennial census is the best and most accurate source for getting demographic data. This section will give a brief overview of what the census is and how it gathers demographic data. When you go to the census website or to American Fact Finder you will likely encounter two different studies. The decennial census is conducted every 10 years. In the census, every person in the U.S. is surveyed and asked a series of ten questions. The American Community Survey is conducted annually using a random sample of American residents and contains a much larger set of questions.
Below is a picture of the 2010 census form with the demographic questions highlighted.
The census includes two questions related to ethnicity and race. Question 8 asks the person whether they are of Hispanic, Latino, or Spanish origin and Question 9 asks for the person's race. These questions are answered independently of one another, and the census provides data on these two questions in multiple ways.
First, the data is available on the race (Black, White, American Indian, etc.) and the ethnicity (Hispanic or Latino) questions as separate topics. For example, a table or variable may offer data on all responses that checked “yes” or “no” to question 8 for Hispanic, Latino, or Spanish origin. This would include all responses to Question 8, regardless of which racial category was picked for question 9. If you use a table or variable structured this way, understand that it will include all racial categories as well in that data. Likewise, if you choose a table or variable that only address the race question, it will include all responses to question 9 regardless of how they answered question 8.
Second, data is available that separates the Hispanic or Latino Question 8 “yes” responses from the Question 9 racial responses. This results in a table with Hispanic “yes” as one variable, and then racial categories for all the “no” responses. So, where some tables or variables would say “White,” these tables or variables would say “Not Hispanic or Latino, White Alone.”
In most instances, FHWA recommends analyzing race and ethnicity census data using tables and variables as described in #2: Hispanic or Latino “yes” answers with “Not Hispanic or Latino” racial group. This will ensure the analyst does not accidentally double-count, potentially reporting a total > 100% of the individual responses.
When analyzing data from the Census, it is important to understand how the data are presented geographically. The Chart below shows the different geographical entities used in the census.
An interactive version of this chart is available at https://www.census.gov/geo/reference/webatlas/
Using the web atlas linked above, the Census provides definitions and examples for each of the listed geographies.
The geographic unit you choose for your analysis will vary based on what it is you are analyzing. Typically, though, for project reviews you will be looking at block groups and tracts (avoid the use of blocks in most situations as the population within them is small and highly variable). And for larger reviews, of statewide programs for instance, you may wish to use a larger geographical entity such as a county.
American Fact Finder
American Fact Finder, formerly available at https://factfinder.census.gov/, was the primary source for gathering the relevant data from the US Census, but the Census Bureau discontinued the site on 3/31/20. The Bureau intends that users find their data primarily on a new website: https://data.census.gov.
This new website is intended to replace FactFinder for all data requests from the US Census. It includes most archived and new Census products, and it features most of FactFinder’s functionality with some new resources for data scientists as well.
The next sections will demonstrate how to gather that information. FHWA will recommend gathering demographic data from table P9 from the 2010 decennial census and table B03002 from the 5-year American Community Survey (ACS). These tables show the Hispanic or Latino population and the not Hispanic or Latino population broken down by race. Using these tables will avoid some of the issues related to the separate race and ethnicity questions discussed earlier.
Note that the census provides other tables with this structure (Decennial P5, for example), but P9 and B03002 will be a useful start. Also, table names can change between each Decennial census, so note that P9 may or may not be the name used for a similar table in the 2020 Decennial census.
Selecting Geographies – Table Search Method.
The example below demonstrates how to gather this data through a simple search to download demographic data at the block group level for Baltimore County, Maryland from the 2010 census.
Step 1: First, navigate to https://data.census.gov, scroll to the middle of the page, and click on “VIEW TABLES.”
Step 2: This is the home page for accessing U.S. Census data. There are several ways to get data, but this guide will start by searching for a table by name. At the top of the page, click on the text box that says “Search” near a magnifying glass icon. Type “P9” (without quotes) and click on the “Search” button. It may take a moment for the page to load.
Step 3: Most tables will show data for the entire country by default, so let’s change our geography first. Click on the “Customize Table” button near the top of the page. From here, the page will display a larger table with many options. For now, click on the “Geographies” button near the top-left of the page to show the geography selection box.
Step 4: Next, select “Block Group” under the “Geography” column on the far left. In the “Within State” column, select “Maryland.” Next, select “Baltimore County” in the Maryland Column and then “All Block Groups within Baltimore County, Maryland.” Clicking in the final column will automatically add the geography to your selections, which you can see at the bottom of the box. If you need to go back, you can click the “Clear Geographies” button. Otherwise, let’s click the “Close” button.
Step 5: The page will display a table with P9 data for the geography you selected. Data.census.gov allows you to click on this table and select your data to copy and paste into a spreadsheet or other document. However, this table will have more data than can be selected this way. To make our analysis easier, let’s download the table into a spreadsheet that Microsoft Excel can read. Click on the “Download” button on the top-right side of the page. Then, click on the “Download” button in lower-right of the box that appears
A box will appear in the middle of the screen with a progress bar. When it is finished, click on the “Download Now” button to save a zip (compressed) file to your computer.
Step 6: Find and open the zip file you downloaded to your computer. Many web browsers will save files to the “Download” folder on your computer by default. Open the zip file, which in this example is called DECENNIALSF12010.P9_data_with_overlays_2020-04-08T115702.csv. Note that the file name will change according to the data requested and the date.
This “csv,” or comma separated values, file will open in most spreadsheet programs like Excel. Note that the “metadata” file will display a list of all variables in the table with descriptions but no other data. The “data_with_overlays” file will have the variable names, description, and the data.
Step 7: With the data downloaded, it can be modified analyzed. For example, Excel can “word wrap” the column headers to make them easier to read. Unneeded columns can be deleted. Percentages can be calculated for all of the race/ethnicity categories. With the “GEOID” column, you can match the data with geographic information system (GIS) programs and other mapping resources. To create population percentages, multiply the total population with the targeted demographic group, such as “Not Hispanic – Asian Alone.”
FHWA has created a macro that, when enabled, can make reading the data easier. It will generate percentages and summarize the area under review after downloading census information. If you would like access to this tool, please email CivilRights.FHWA@dot.gov.
Selecting Geographies – Map Method
An alternative to selecting the geographic area from the “Customize Table” menu is to use the map selection method within data.census.gov. This can be useful for narrowing a search to fit a smaller or more specialized area. This example will demonstrate how to use the map in Data.Census.Gov to select a P9 table with census blocks in downtown Baltimore, Maryland
Step 1: Search for the P9 table in the top search bar like the prior example. Instead of customizing the table, click on “MAPS” in the upper-left section of the page. The page will display blank map of the United States.
Step 2: Next, zoom and drag the map to the area in central Baltimore, Maryland. Unlike the map function in FactFinder, Data.Census.Gov does not currently allow users to search for a specific address or place, and the map does not display all place and street names.
Step 3: Click on the drop-down box in the upper-right next to “Geographies,” and select “Census Block.”
Step 4: The map will display numbered outlines of the census tracts in the area. Click on “Select” in the upper-left. Click and hold on the map to draw a rectangle and unclick when finished. After a moment, the map will highlight the selected blocks in grey borders. Drawing another box will select additional blocks for the table.
If this is not the area desired, click “Clear Geos” in the upper-left to clear the selection. If a large number of blocks are selected, a message will display at the top of the page: “The amount of geographies you’ve selected exceeds the character limit for the URL to be shareable or bookmarked.” This message can be ignored.
Step 5: To download the file, click on the box next to the P9 table name (“Hispanic or Latino, and Not Hispanic or Latino by Race”) on the top-left. Then, click “Download Selected” in the top-left. A box will appear near the bottom of the page—click the “Download” button to download a zip file as before.