What the evidence says
The evidence on body-worn cameras (BWCs) and racial disparities comes almost entirely from one source, a difference-in-differences study of BWC deployment across 22 Chicago police districts in 2016-2017, plus one hedged, unquantified claim about stop frequency from a separate review. On stop frequency itself, officers wearing BWCs conduct fewer stops than officers without them and may divert their activity to other tasks, but this claim carries no quantified magnitude and is stated with explicit hedging ("may"), so it establishes direction only, not size.
The bulk of the evidence instead measures BWC effects on how citizen complaints against officers are resolved, not on stops directly. BWC deployment decreases the likelihood of a "not sustained" finding (a complaint closed for insufficient evidence) by approximately 9-10 percentage points, though this point estimate was not distinguishable from zero in the baseline model. In the same data, BWC deployment increases the likelihood of a "sustained" finding (a complaint with enough evidence to justify discipline) by 9.9 percentage points, equivalent to a 64% increase relative to a 15.4% baseline sustained rate — an estimate the source reports as robust, with parallel-trends assumptions validated and placebo event-study tests not distinguishable from zero.
Within the "not sustained" outcome, the pre-existing racial gap narrows after BWC deployment. Before BWC deployment, 53% of Black complainants' cases were closed "not sustained" versus 38% of White complainants' cases; after deployment, those rates fell to 18% for Black complainants and 16% for White complainants. Modeled as an interaction effect, BWC deployment decreases the not-sustained rate by 16.2 percentage points for Black and Hispanic complainants relative to White complainants, though only the Black-complainant estimate is distinguishable from zero at conventional thresholds — the Hispanic estimate is not.
The "sustained" outcome tells a different story. Sustained rates rise for every racial group after BWC deployment — to 45% for White complainants, 31% for Black complainants, and 27% for Hispanic complainants — but the size of the BWC-attributable increase does not measurably differ by race: the Black and Hispanic interaction terms are both small and not distinguishable from zero. In other words, BWC deployment raises sustained-finding rates roughly uniformly across racial groups, so the descriptive gap between White and Black/Hispanic sustained rates persists after deployment even though it narrows for not-sustained findings.
The claims on this page do not measure racial or ethnic disparities in stops themselves — who gets stopped, at what rate, or by race — despite that being the topic's framing. What exists instead is a measure of racial disparity in how complaints from those stops (or other citizen interactions) are adjudicated afterward. That is a distinct outcome, and no claim here bridges the two.