“Community Policing” aims to make trusted partners out of police and the residents they serve by engaging police more deeply in the neighborhoods they patrol. The strategy germinated in the chaos of the 1960s, had a heyday in the 1980s under advocates like Lee Brown, then the chief of the Houston Police Department, but ran into resistance from rank-and-file cops. Blessed by the Obama administration, and spurred by Ferguson and other evidence of a gulf between police and the public, community policing is enjoying a comeback, and with it, a new interest in polling as a policing tool.

John Linder, now a consultant with the New York Police Department, has been surveying big city cops since the early 1990s. In what he describes as the biggest project of his career, Linder is developing a real-time measure of police-community trust, called a “sentiment meter,” which he hopes will fold into NYPD’s weekly review of crime fighting data, called CompStat. The Marshall Project’s Simone Weichselbaum talked to Linder about polling as a policing tool. The interview has been edited for length and clarity.

What exactly is a sentiment meter?

If it works, it will be a system that will deliver to police and their executives real-time measures of public attitudes — whether trust is going up or down, whether the sense of safety is going up or down, and whether the job approval of the NYPD is going up or down—by neighborhood. The metrics of CompStat, which have always included crime and police activity, may in the foreseeable future include measures of trust, safety, and the job approval of the NYPD by every sector of the city on a continuous basis.

If the NYPD adopts your plan, then what? Will police commanders lose their jobs if the community satisfaction score in a particular precinct is low?

Not initially, I don't think. It will help precinct commanders take corrective action if these metrics are going in the wrong direction. It's a tool for them to have a reality check coming from the people they're trying to serve and protect.

Why should the public trust this sentiment meter? The past presidential election cycle showed us that surveying people on uncomfortable topics — who they plan to vote for, or in this case, what they think about local cops — produces unreliable results.

The guys designing our technology used it to predict exactly the presidential-election results in Ohio and Michigan, and Brexit in the UK. I think they may have found a way around selection bias in polling, which was a major reason most pollsters missed the Trump phenomenon.

How has police polling changed since you started?

In the early 1990s, Police Commissioner Lee Brown [then the chief in New York] asked me how to change the NYPD culture to embrace community policing, which was cops on foot beats asking citizens what they wanted the police to do. I did hundreds of cop focus groups and then sent them all a questionnaire. Polling was an inward-focused management tool. I defined the NYPD culture and made recommendations what to do, but I didn’t survey the people of New York.

Back then, the crime was four times as high as now, murder seven times as high. Jack Maple, a Transit Police lieutenant who two years later co-invented CompStat, said to me, ‘I don't think we need to ask the public what they want. What we need is to keep their babies from getting killed in cribs by stray bullets flying through their windows. That's what they want, that's what they need. Let's go do it.’

Today, crime in New York, unlike some other cities, is 75 percent lower. Murder and shootings have been cut by four-fifths. And (Police Commissioner James) O’Neill wants to keep driving it lower. The reason he has the job is that he knows the only way to keep doing that is to get everybody into the game, not just police, but also the people who live In the neighborhoods where the crime is happening. To some extent people have been willing to report crimes. To a lesser extent they've been willing to testify. So what they feel and believe matters. He (and Commissioner Bratton) hired me to help the department find out.

CompStat helped drive down crime by getting police to focus on where the crime was occurring, and hyper focus on those areas. How does a sentiment meter bring down crime?

If we can find a way to give the commanders of the NYPD real time data on what people feel, then police brass can tailor strategies and tactics in response. It can give them more than just crime statistics, police activity (arrests, summonses, stop-question-frisks, case closures by detectives) to guide what they do and don’t do. That’s what O’Neill has told us to deliver.

So how can that work?

We are trying to deliver three measures. One: a measure of trust of the police. Two: a measure of the sense of safety in your neighborhood versus your sense of safety in the city at large. Three: your overall approval, job approval rating of the NYPD.

The early indications are that we will be able to deliver what O’Neill is looking for.

In real time? Are you kidding?

This is not traditional polling. This is an algorithmically governed sentiment meter that is gathering tens of thousands of data points 24/7, 365 days a year.

CompStat has been a staple in American policing for more than a generation. Why did it take so long for policing experts like yourself to fold community trust into the metrics?

I’m not a policing expert; I have cultural change tools strong leaders can use. But the answer to your question about why so long: A. We have the technology available now to do it. B. Crime is low enough that to drive it lower we need to try new things. And C. This police commissioner has determined that he needs to manage the police department in a way that builds trust rather than decreases it.