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Indicator Selection Process

The selection of the Transportation Health Tool (THT) indicators began with a kickoff meeting involving the CDC, USDOT, and the American Public Health Association (APHA) in 2012.  

With guidance from the kickoff meeting and over the course of several months, APHA led an intensive process to identify, review, and refine the health and transportation indicators. The term “indicator” was used broadly for factors that might be considered and included in the THT. These included indicators associated with

  • health, such as physical activity, air quality, or injury rates;
  • transportation, such as vehicle miles traveled or walkability;
  • policy, such as complete streets or safe routes to schools; and
  • infrastructure investments, such as funding for transit or active transportation, such as walking and biking paths.

The initial 190 potential indicators were narrowed to the 45 considered to have the most promise and ease of understanding to affect at least one of the following areas:

  • physical activity,
  • safety,
  • air quality impacts, and
  • access to goods and services.

To further refine the indicators, APHA contracted with Planning Communities, LLC, to conduct a literature review and synthesize the data and evidence for each indicator. The planning team followed a three-step process to develop, evaluate, and recommend indicators for the THT:

  1. Refine and expand an initial list of 45 indicators to clarify definitions and fill identified gaps
  2. Develop indicator evaluation criteria through a facilitated workshop
  3. Review and evaluate indicators against the identified criteria to inform selection of a condensed set of THT indicators

The following seven evaluation criteria were created based on input from subject matter experts and the Project Team:

  • Data Availability and Level
  • Feasibility
  • Technically Valid
  • Timeliness
  • Clarity/Openness/Transparency
  • Health Equity
  • Connectivity of Indicators

Through this process, the list of 45 indicators was narrowed to the 34 having the greatest evidence-base and most potential to demonstrate the connection between transportation and health.

The final list of 14 indicators was developed through feedback from experts during a 2-day workshop in 2013, and additional work by the project team. APHA, along with CDC and USDOT, selected 48 participants for the workshop who had expertise in health and transportation. Those participants had expertise in one or more of the four main areas of interest (physical activity, safety, air quality, or access) or other special areas (e.g., tool and web development). During the workshop, the expert panel made recommendations about the THT, provided input on the selection of key indicators to be included in the THT, and advised on scoring.

A process was used to compare the top indicators identified during the workshop and the indicators selected through the project team and expert guidance. This process resulted in the selection of the 14 final indicators to be included in the THT.

Through an extensive review of the health and transportation literature, these indicators proved to have the strongest evidence base (linking health to transportation). National data also show connections between transportation and health for these indicators for states and regions across the United States.