When Seconds Count

By Mike Williams

What if you could cut 10 seconds off the response time of that ambulance — the one responding to a family member’s or friend’s emergency? A team of Rice data experts discovered that would be the result of adding five ambulances to southwest neighborhoods served by the Houston Fire Department (HFD) Emergency Medical Services program. The added ambulances would also cut down on citywide “chain reactions” that force emergency personnel from distant stations to respond when local medics or fire personnel are tied up.

The recommendation is the result of months of number-crunching by students working in the Center for Transforming Data to Knowledge (D2K) Lab in Rice’s Brown School of Engineering. Founded and directed by Rice statistician Genevera Allen ’06, the D2K Lab provides opportunities for students to work directly with companies, academic labs, government agencies and nonprofits to translate data into actionable ideas.

Former students Ashwin Varma, Shannon Chen, Erin Kreus, Jesse Pan and Lynn Zhu, all statistics majors who graduated in 2019, crunched the numbers. They were advised by Anastasios “Tasos” Kyrillidis, the Noah Harding Assistant Professor of Computer Science.

They analyzed data on more than 2 million HFD emergency calls between 2012 and 2018 and measured not only response times by ambulances and fire trucks, but also how chain reactions lengthen times when personnel and vehicles have to respond to emergencies outside their own districts.

“If you can reduce the number of times that any given station calls for help outside of its territory, you are preemptively preventing a chain reaction from occurring … not just in the district [where] you added the vehicles, but in other districts as well,” Varma said. That, he said, motivated the team. “We looked at the dispatch algorithms, and we looked at years of past information seeking to see if we can find a disruptive strategy that we could use to minimize the risk at an incident and match the appropriate resource with the risk of that call type,” said Assistant Fire Chief Ruy Lozano.

The students also agreed that HFD’s quest to improve its response to medical emergencies is worth pursuing. Fire-related calls account for only 12% of those received by HFD. “The vast majority are EMS incidents,” Varma said. “However, 58% of the HFD’s fleet consists of engines and ladders; 42% are EMS vehicles,” he noted. “The increase in the total incidents is completely driven by EMS call volume. That has increased over 20% in the last six years.”

“This is a really good first step to be able to use empirical data to drive our future decisionmaking,” Lozano said.