The New York Police Department on Thursday said it will suspend exams taken by prospective recruits for three months beginning in July as it looks to clear a 50,000-person backlog of applicants and overhaul an unwieldy hiring program that has become unmanageable.

The department made the decision to suspend the exam after conducting a survey in the spring of 1,200 people who dropped out of the recruitment process. The survey showed a common theme: Many choose to enter other careers because it can take up to four years before...