Dr. Thomas Farley knows his way around a stethoscope. But the former commissioner of New York City’s Department of Health and Mental Hygiene is also practiced in effectively implementing and measuring the impact of public health messaging.

“I’m an extremely big data person,” said Farley, who was recently appointed commissioner of the Philadelphia Department of Health. “Ideas are great, but you have to measure what actually happens.”

Farley’s health department helped cut smoking rates in NYC by a third under then-mayor Michael Bloomberg, dropping the total amount of smokers in the city from 21.5 to 14 percent — that’s 400,000 people, according to Farley.

The city also saw declines in the consumption of sugary drinks and childhood obesity, as well as “remarkable increases in life expectancy which were far greater than the nation as a whole,” Farley said. Under Farley, NYC’s health department also introduced a letter grading system for restaurants and helped physicians implement electronic health records.

“Every initiative we did, we had a strong evaluation plan and had larger measurement systems to track how we were doing,” he said, the single most important of those systems being an annual telephone survey that collected data on health conditions and behaviors like obesity and smoking, respectively.

But Farley is as much an ad man as he is a data nut. He helped spearhead anti-smoking campaigns that placed special emphasis on the gruesome effects of long-term cigarette use — a messaging initiative that influenced the national Tips From Former Smokers campaign.

It was all part of Farley’s system.

“When we ran a specific media campaign, we would do surveys specific to that [campaign] a few months afterwards to measure recall and what people said about the campaign,” he said.

He brought that expertise to the nonprofit sector after leaving his public post in 2014, helping to launch The Public Good Projects, a communications nonprofit working to promote health through mass media. Farley said it’s the same sort of public health advertising he did as NYC’s health commissioner.

“I feel now and feel from before that public health messages are things everybody needs to hear, and using the power of mass media makes an awful lot of sense,” he said.

Even though Farley just spent a year helping to get the fledgling organization on its feet — they’re still working on their first campaign — he’ll be leaving this month to assume his new position here in Philly. He said he’ll still do some “informal consulting” with TPGP to make sure they “continue to thrive,” but he’s excited to get to work as Philly’s new top doc.

As for his priorities? The appointment is still super fresh — he said he hasn’t spent the night in Philadelphia yet and hasn’t had an opportunity to meet his staff, let alone truly delve into what his agenda will look like. But he’s coming to the table with a stacked resume.

As for that data-savvy, message-heavy approach to improving public health? That’s part of the package.

“The only way you can know how you’re doing is to measure the health of lots of people and that requires collecting data … and analyzing it, and then communicating it, not just internally within the health department, but also to other community leaders and to the city as a whole,” Farley said. “You will see an awful lot of data reports and a lot of discussion of that when I’m there.”