Mean time of repair (MTR) = (Sum of all repair times)/(Number of of breakdowns) Machine breakdown severity = (Cost of breakdown repairs)/(Number of of breakdowns) Percentage of planned maintenance = (Number of maintenance hours worked as planned)/(Total maintenance hours worked) Maintenance efficiency = (Actual hours worked on aintenance)/(Total available hours for maintenance) Effective cost of labor/hour = (Total cost of labor (wages and overtime))/(Actual hours worked) Effective cost of maintenance/man/hour (1) = (total cost of maintenance)/(total man hours worked) (2) = (direct cost of breakdown repairs (labor and material)/(total direct cost of all maintenance) For more on indices refer to Chapter 2 on maintenance productivity in this book.