The New York Police Department announced Tuesday that it would disband a special unit charged with detecting terrorist threats by secretly conducting surveillance on Muslims in New York. Applauded by Muslim and civil rights organizations, such a move could actually boost U.S. counterterrorism efforts, according to data from the Muslim American National Opinion Survey (MANOS) of which I am the principal investigator.

The Muslim-American community has served as a major resource for law enforcement since 9/11, with some scholars citing Muslim-Americans as the single largest source of initial information leading to disrupted terrorism plots since 2001. Such community assistance is particularly important in stopping homegrown attacks which tend to involve more “lone wolf” actors, making them more difficult to detect by law enforcement. Indeed, it was a Muslim immigrant who first reported suspicious activity in the 2010 case of Faisal Shazad, convicted in the Times Square bombing attempt.

The NYPD’s spying tactics, guided by a former CIA official, stirred debate over whether the NYPD was infringing on the civil rights of Muslims and illegally engaging in religious and ethnic profiling. Findings from recent studies based on MANOS data– a nationally representative survey of 500 Muslim-American respondents collected online by YouGov in March 2013 –suggest that such programs that unfairly target Muslim communities can create feelings of cynicism and reduce Muslims’ willingness to voluntarily assist police in criminal investigations.

The MANOS data reveal that even after accounting for a variety of background features and baseline attitudes about police, the 13 percent of Muslim respondents living in New York are significantly more cynical about how police will likely treat a Muslim criminal suspect, compared to other Muslims across the country.

In a paper assessing how Muslim-Americans develop opinions about U.S. law enforcement, I find that those who are most familiar with the American system and its laws are best able to identify when law enforcement is violating its principles of equality and fairness. Using a randomized experiment, I find that U.S.-born Muslims are 17 percent less likely to say that police will behave fairly when dealing with a Muslim suspect, compared to a non-Muslim suspect. This is a striking difference relative to the beliefs of foreign-born Muslims, who like other U.S. immigrants are significantly more trusting of police.

In a related paper, I show using regression analysis that these expectations of fairness are directly related to willingness to help law enforcement. Figure 3 shows that U.S.-born Muslims are significantly less willing to provide police information on a criminal case involving a Muslim suspect.

By accounting for differences in expectations of fair treatment however, the gap between assisting police when the suspect is Muslim compared to a non-Muslim closes substantially. Believing police will behave fairly boosts U.S.-born Muslims’ level of assistance by over 30 percent when the suspect is a Muslim.

The MANOS data, to my knowledge, is the first nationally-representative sample of Muslim-Americans that is able to compare attitudes and expressed willingness to assist police based on the identity of the suspect (the project was sponsored by the National Science Foundation). While opinion data have limitations, the findings here echo the statements of scholars and policymakers who warn that heavy-handed police investigations that disproportionately target Muslims can lead citizens to become less comfortable with reaching out to law enforcement when they have concerns about a potential terrorist.

While terrorism in the U.S. remains a serious threat, the measurable results of the NYPD spying program appear to be less than desirable. In addition to potentially suppressing voluntary assistance from the Muslim-American community, after years of collecting information, the NYPD acknowledged that the unit never generated a lead.

“Our administration has promised the people of New York a police force that keeps our city safe, but that is also respectful and fair,” New York Mayor Bill de Blasio said in a statement regarding the cessation of the NYPD spying program. “This reform is a critical step forward in easing tensions between the police and the communities they serve, so that our cops and our citizens can help one another go after the real bad guys.”

While some suspect the move was motivated by political reasons rather than justice, the decision marks a clear move away from early post-9/11 policies upheld under the leadership of previous NYPD Commissioner Raymond Kelly.

Rachel Gillum is a fellow at the Center for International Security and Cooperation (CISAC) and a doctoral candidate in Political Science at Stanford University. She is principal investigator of the Muslim-American National Opinion Survey (MANOS) and is affiliated with the Association for Analytic Learning about Islam and Muslim Societies and with Stanford’s Abbasi Program in Islamic Studies.