User Guide

Navigating the Map

To view the H+T Index, click on View the Index in the upper left hand corner of the website or on the Use the H+T Index box.

Clicking on either link will take you to a map of the United States where you can either zoom into a desired area or use the Find search bar at the top of the page. Locations that appear in green text are regions, those that appear in blue are Census defined places. This search bar will remain above the maps and can be used to change regions or find a specific location within a region.

After a location has been chosen, the default map view presents side-by-side comparisons of housing costs as a percent of area median income and housing + transportation costs as a percent of area median income.

You can pan around the map using the zoom bar and navigation tool.

Clicking on the map will bring up a dialogue box with data for the selected block group as well as aggregate data pertaining the region, county and municipality in which the block group is located.

The Map View tool above the right hand map allows you to view one map at a time, which results in an expanded map and legend.

Custom Map Comparisons

The default map view after a location has been selected is side by side comparisons of housing costs as a percent of area median income and housing + transportation costs as a percent of area median income.

In addition to the preset map comparison, there are a wide range of other variables that can be viewed. To bring up the complete list of variables available on the H+T Index, click on the name of the variable current displayed on the map.

Both inputs and outputs from the transportation costs model are included on the list of variables which is organized into categories: Two Views of Affordability; Affordability Indices; Household Model Outputs; Greenhouse Gas from Household Auto Use; Model Inputs — Environmental Variables; Model Inputs — Household Variables; and Housing Costs.

After a variable has been selected, the dialogue box will close and the map will update. If you choose not to change the variable being view on the map, click on the X in the upper right hand corner to close the box.

In addition to assessing relationships among variables, the two map view can be used to compare different geographies within a region or different regions. Normally when you type a location into the Find bar both maps will zoom to the selected geography. However, clicking on the lock symbol will bring up another Find bar.

This allows you to select geographies for each map separately. For example, below transportation costs are shown as a percent of income in the Chicago and Los Angeles metro regions. Locations can be compared within the same region and at different scales as well.

When you want the geographies to update simultaneously, click on the grey open lock symbol and the second Find bar will be removed.

Household Income Variables

When a region is selected, the default display is data modeled for the Regional Typical Household.

The Regional Typical Household assumes a household earning the median income for the region, with the average household size for the region, and the average number of commuters per household for the region. An important aspect of the H+T Index is that transportation costs are modeled for the “typical” household in a region, or the household represented by these three values.

By fixing income, household size, and commuters, the model controls for the impact of these variables on transportation costs. Differences in transportation costs are therefore a result of neighborhood characteristics and variation in the built environment. When variables are shown as a percent of income, this median income value is used. Therefore, the variable can be interpreted as the cost impact of a given location on the average household in the region.

CNT has modeled and reported data for three typical households, each with a different income level. To change the household income variable, click on the name of the variable current displayed on the map. This brings up complete list of variables available on the H+T Index. The three household variables are listed at the top of the variable box.

The first is the Regional Typical Household, with its assumptions described above. Second is the Regional Moderate Household, which assumes a household income of 80% of the regional median, the regional average household size, and the regional average commuters per household. Third, the National Typical Household assumes a household income of $51,425 (the national median household income), a national average household size of 2.6, and a national average number of commuters per household of 1.15.

Legends

Several different legends are available to help users interpret the data presented on the map(s). The default legend is a key illustrating the value ranges represented by the colors on the map. In the two-map view, additional legends can be viewed by clicking on the arrow to the right of the key (in the one-map view all the legends are displayed at once).

This brings up a drop-down menu of the legends that are available.

Description explains the selected variable.

Summary Table of Statistics includes the count of Census block groups, the total number of households, the minimum value of the variable, the maximum value and the average value. The statistics can be displayed for six different area of focus: the region, the map area, as well as any county, municipality, MPO or Congressional district within the region. These areas of focus are also available for all the legends described below.

If you select county, municipality, MPO boundary or Congressional districts, a second drop down menu will appear listing all the places pertaining to the selected area of focus within the region.

Graphical Legend shows the count of block groups in each color/variable range.

Histogram Legend shows a bar chart representing the frequency distribution of the count of block groups for each value of the given variable, with the range showing the 5th to 95th percentiles.

Population Statistics shows the count and percentage of the population within each of the variable ranges.

Household Statistics and Neighborhood Statistics have the same functionality as Population Statistics, but show counts and percentages for households and neighborhoods (block groups), respectively.