A new study about police stop-and-frisk encounters in Newark found that one quarter of police stops ended in an arrest or a summons, about twice as often as they do in New York City.

The study, by the American Civil Liberties Union of New Jersey, is the first to examine the stop-and-frisk practices of the Newark Police Department, which only last year began publicly releasing data about street stops.

The group’s executive director, Udi Ofer, said that new data could help to spur a public debate in Newark about stop-and-frisk police tactics similar to the one that led to a drastic curtailing of police stops in New York City.

Mr. Ofer said that the data from Newark, although limited, nonetheless depicted “a troubling picture of stop and frisk in Newark.”