Mills used data from the Harborview Medical Center Trauma Registry and Washington State death records to analyze 670 fatal and non-fatal firearm assault injuries that occurred in King County between 2010 and 2014. She found that the median distance between the location of injury and the individual’s address was almost 4 miles, with the greatest distance between residence and injury location seen amongst young people. Mills also discovered most missing residential addresses in these records were due to assaults on the homeless or people who live outside the county. This type of missing information introduces bias into a residential-based database because it excludes the homeless and unstably housed or it misrepresents an injury hotspot where injuries occur primarily to nonresidents.