My latest client was a Fire Chief who was facing pressure from city management to change from a 24-hour schedule (48/96) to an 8-hour schedule. I assume that the city officials mistakenly believed that 8-hour schedules don't have any overtime in them. Like many public agencies, they think all overtime is bad and should be eliminated. 

I started by showing the Chief what the current schedule looked like on a spreadsheet. It's a 6-week pattern with 6 teams working an average of 56 hours a week. The only way to get rid of the overtime is to add more staff. Shall I repeat that? The ONLY WAY to get rid of the overtime is by hiring more staff. Not changing the shift length. Not changing the work pattern. MORE EMPLOYEES is the only way.

With his coverage requirements (4 people at all times), the current schedule required 12 employees. By increasing the staff to 16, they could lower the average hours worked to 42 hours/week. It didn't matter whether they used 8-hour, 12-hour, or 24-hour shifts. All three approaches (with the exception of 8-hour fixed shifts, which would require 18 people) would need 16 employees averaging 42 hours a week.

What the city folks should have asked was:

1. Would adding 4 more employees cost less than the current approach (12 employees at 56 hours/week vs. 16 employees at 42 hours/week)?
   
   
2. And, if it is, is it worth disrupting the workforce and causing numerous personnel issues?

Overtime is really a substitute for staffing. In 24/7 operations, a little overtime can save a bundle. In this city's case, the answer is not so clear. However, the belief that changing to a different shift length would eliminate the overtime is not accurate. The only way to lower the overtime would be to hire more staff.