Observing that only about 12 percent of police stops resulted in an arrest or summons, Judge Scheindlin, who is hearing the case without a jury, focused her remarks on Monday on the other 88 percent of stops, in which the police did not find evidence of criminality after a stop. She characterized that as “a high error rate” and remarked to a lawyer representing the city, “You reasonably suspect something and you’re wrong 90 percent of the time.”