In what could signal a turnaround regarding concerns about the hiring pool for the managerial ranks of the New York Police Department, police officers are flooding preparation courses for an upcoming exam required for promotion.

The spike in attendance at prep courses for the next sergeant’s exam, scheduled for January 26, could help ease the concerns of Commissioner Raymond Kelly, who has pointed to the recent low turnouts and passing rates as an example of the department’s problems in filling managerial positions.

Attendance at one of the most attended such schools in the city, the Key, is up to 1,500 officers from about 850 who paid to attend the first sergeant’s exam class in February, an instructor and retired captain in the New York City Police Department, John Monaghan, said. At Mr. Monaghan’s first class for the exam on Thursday, hundreds of officers filled the basement auditorium of St. Andrews Church in downtown Manhattan.

In the eyes of many experts, including Mr. Monaghan, the high turnout for the prep courses correlates with a tentative agreement reached between the city and the Sergeants Benevolent Association that would lift top salaries above $100,000.

While more are signing up for the prep courses, which last 18 weeks and cost as much as $499, the officers still have to pass the test, which at least one police expert said has become too difficult. “It has become an area of concern that the sergeant’s exam has become a lampoon for asking esoteric questions,” a professor at the John Jay College of Criminal Justice, Eugene O’Donnell, said.