RAC Heat Map

The Speir Research Group in the Department of Forensic and Investigative Science at West Virginia University currently houses a database of over 2000 shoes. To date, 1300 shoes have been fully analyzed, identifying a total of 72,306 randomly acquired characteristics (RACs). These RACs have been classified based on outsole location and shape; shape classes include irregular, elongated and approximately isometric geometries. This webpage provides the user with access to an interactive heat map detailing RAC frequency in terms of location and shape for a normalized shoe.

In the following frequency table, numerical values in the shaded row remain constant regardless of the user's interaction with the heat map, displaying data associated with total RAC count for the entire database (regardless of cell location). Conversely, the three unshaded rows automatically update to display RAC count and frequency for individual cells (5 mm x 5 mm) selected by the user (please select a location/cell of interest using a left mouse click). For more information about data included in the table, please see the bottom of this page for further description.

Few RACs     Many RACs

All RACs in Database: Reports the total number of RACs in the database, irrespective of location.

All RACs in Cell: Reports the total number of RACs at a specific location.

Chance of Finding RAC in Cell: Reports the empirical frequency of finding a RAC at a specific location.

Chance of RAC Co-Occurrence: Reports the empirical frequency of selecting two shoes at random and finding a positional match at a specific location.

Similarities & Likelihood Ratios: Redirects the user to secondary webpages that report the similarity of RACs with positional co-occurrence, originating from different outsoles.

The content on this web site was funded through a grant from the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice (2013-DN-BX-K043). Neither the U.S. Department of Justice nor any of its components operate, control, are responsible for, or necessarily endorse, this web site (including, without limitation, its content, technical infrastructure, policies, and any services or tools provided).