Lower West Side sexual assault is up 109% against its multi-year baseline, the strongest single signal in Chicago this month. Three of the top five signals this briefing are sexual assault, with West Pullman and Douglas alongside Lower West Side, a concentration in one category that makes this month structurally different from recent briefings.
Citywide volume is down 4.7% against the prior 12 months, 129,420 incidents against 135,839. The mix runs heavily toward sustained and below-trend signals, 57 sustained-shift and 38 below-trend against 9 spikes across 77 neighborhoods. Outside of sexual assault, Gage Park other-larceny and Beverly aggravated assault were the other fresh spikes in the top five.
The sexual assault pattern across three neighborhoods is the one to watch going into September. This is the first month it has topped the rankings, so there is no established run to confirm a structural shift, but the breadth across Lower West Side, West Pullman, and Douglas in a single month is unusual. The citywide decline otherwise holds, and the sustained-shift signals continue to dominate the broader picture.
Sustained drops worth naming
Robbery ran below trend in the trailing 12 months — 32% down from the year before. Sustained shifts often precede a baseline reset; we surface them at the same prominence as spikes.
How last month's forecasts performed
Forecasts for August were issued from data through July 2026. 9 of 9 citywide bucket forecasts (100%) landed inside their 95% prediction intervals.
| Category | Predicted | Actual | Error | In CI |
|---|---|---|---|---|
| Aggravated Assault | 1186[1063–1310] | 1164 | 1.9% | INSIDE |
| Arson | 38[21–56] | 37 | 3.1% | INSIDE |
| Burglary | 620[424–802] | 551 | 12.4% | INSIDE |
| Homicide | 44[26–63] | 40 | 10.5% | INSIDE |
| Motor Vehicle Theft | 2034[1121–2880] | 1613 | 26.1% | INSIDE |
| Other Larceny | 5979[4777–7049] | 5244 | 14.0% | INSIDE |
| Robbery | 528[316–735] | 536 | 1.6% | INSIDE |
| Sexual Assault | 286[255–319] | 294 | 2.8% | INSIDE |
| Vandalism | 2384[2135–2612] | 2417 | 1.4% | INSIDE |
Per-bucket coverage, MAPE, and bias across the full 12-month horizon live on the methodology page.
Public Analyst.ai, “August 2026 — Chicago,” archived snapshot.Permanent URL: /chicago/2026/august