Cities Are Killing Rats With Data

It was the spring of 2013 and rats were on the rise in Philly. A particularly mild winter, coming on the heels of another mild winter the year prior, resulted in an uptick of reports to the city’s Rat Complaint Line. Calls jumped 31 percent year over year in February and March of 2013. Then came the panic over a rat invasion in Rittenhouse Square.

It was a particularly problematic season for rats not only in Philly but in cities across the East and Midwest. That included Somerville, Massachusetts (population 78,804) which had a boom in rats following successive warm winters. Rat populations often ebb and flow based on temperature variations, but the city was determined that controlling other factors could prevent an outbreak from ever happening again. It inspired Somerville to enlist predictive analytics in the cause of rat abatement. Moneyball for pest control, basically.

That fall, civic leaders founded the Rodent Action Team (aka RAT — cute, isn’t it?), which began mapping where rats appeared around town. They saw a distinct pattern: rat sightings and breeding grounds were clearly clustered around food sources. To mitigate the problem, the city made improvements to trash collection in targeted areas, as Henry Grabar reports for Next City:

The city quadrupled the number of waste container licenses it issued to restaurants. It bought 64-gallon trash cans for every house in the city. After all, if residential garbage pickup and disposal is a municipal service, why not garbage storage? Standardizing the city’s bins was first and foremost a RAT initiative, but the result was aesthetically pleasant too.

Two years later, the city’s rat population has declined significantly. Although a couple of rough winters certainly helped, Somerville’s efforts appear to have borne out results: the city’s rat population has shrunk 40 percent more than neighboring Boston.

Somerville was standing on the shoulders of Chicago, which fostered a similar strategy in ridding itself of rats in the summer of 2013. The city developed an algorithm for predicting areas at increased risk of rat spawning. Variables like overflowing trash, food poisoning in restaurants, water main breaks, and, of course, rat-control requests — all pulled from 311 call data — were predictors of breeding grounds. Writes Sean Thornton for Data-Smart City Solutions:

For example, the analytics team found that in certain sections of Chicago, a 311 call or online request related to garbage produces a 7-day window in which an increased number of rodent calls will occur in the same area.   Thus, rates of garbage-categorized 311 calls serve as a measurable indicator whose direction can signal changes in rat trends.

And given the alarmingly rapid rate of rat reproduction (they’re capable of producing 15,000 offspring in a single year under ideal conditions), destroying prime breeding grounds was the key to minimizing the population. The city’s sanitation department sweeps through the forecasted hotspots and eliminates food sources for the rats; namely, trash. Rat complaints are down 3.6 percent in the Windy City  compared to 2013.

Other cities are taking notice, evidenced by Baltimore’s new rat-eradication team that is using some of the predictive-analystics techniques honed in the Windy City. There’s no such movement of Philly, where the city’s system of rat maintenance is largely reactive, rather than predictive. Health inspectors respond to calls on The Rat Complaint, neutralizing the problem and recommending ways to deter rodents in the future.

Of course, one might question whether expertise and resources for data-crunching should be allocated to rat reduction, rather than crime or budgetary excess. But, given that all it took to make inroads on rats in Somerville was a few hours a week worth of work from a small five-person department of data analysts, it’s something to consider in Philly.