Killed by Police: Validity of Media-Based Data and Misclassification of Death Certificates in Massachusetts, 2004-2016
To assess the validity of demographic data reported in news media-based data sets for persons killed by police in Massachusetts (2004-2016) and to evaluate misclassification of these deaths in vital statistics mortality data.Methods
We identified 84 deaths resulting from police intervention in 4 news media-based data sources (WGBH News, Fatal Encounters, The Guardian, and The Washington Post) and, via record linkage, conducted matched-pair analyses with the Massachusetts mortality data.Results
Compared with death certificates, there was near-perfect correlation for age in all sources (Pearson r > 0.99) and perfect concordance for gender. Agreement for race/ethnicity ranged from perfect (The Counted and The Washington Post) to high (Fatal Encounters Cohen's κ = 0.92). Among the 78 decedents for whom finalized International Classification of Diseases, 10th Revision (ICD-10), codes were available, 59 (75.6%) were properly classified as “deaths due to legal intervention.”Conclusions
In Massachusetts, the 4 media-based sources on persons killed by police provide valid demographic data. Misclassification of deaths due to legal intervention in the mortality data does, however, remain a problem. Replication of the study in other states and nationally is warranted.