The Ottawa shift system uses five duty groups working three shifts on a 35-day work pattern with the day split into a 10-hour morning/afternoon shift, a 10-hour afternoon/evening shift and an 8 and 1/2-hour night shift. Advantages include better matching of resources to demand, more thorough and rapid investigations as a result of longer shifts, and reduced officer fatigue owing to removal of rapid shift changeovers and longer rests after working nights. Disadvantages include the difficulty of maintaining manning levels on any shift with the move from four to five duty groups unless additional officers are employed, difficulties in arranging shift overlaps to coincide with peaks in established crime patterns, and the systemþs unsuitability for rural areas where crime is less predictable and geographical size is a barrier to a policing presence. Tables, references