Maintenance success is commonly measured by the yardstick of outcomes such as the change in downtime since last month. The problem with using outcome-based metrics for this purpose is they include a factor called luck. Thus, they cannot accurately tell you if maintenance is successful.
You can do everything right but still have a failure because you had the back luck of installing a motor whose windings were varnished on a day when the drying oven was experiencing problems. You can make many mistakes, but not have a failure because some factor beyond your control was enough to prevent that failure.
This dynamic is in play when it comes to safety. We see people performing unsafe acts but not getting hurt. Often, these people completely discount the role of luck and take “it hasn’t happened to me” (yet) as “it won’t happen to me.” Until their luck runs out.
To measure maintenance success, evaluate your maintenance practices and how well people execute them.
