Here are some considerations for cleaning up or editing an event history:

• Remove all events that have nothing to do with earning service
  • All events before the first start event
  • Married/divorced, new child, transferred to another location (that doesn't stop service accruals)
• If multiple events occur on the same date, only keep the event that drives the service calculation. For example, when you transfer to another plan, was a stop event created for the current plan and a start event created for the new plan?
  • Did service accruals stop when you switched plans? Then, remove the start event from the service event history.
  • If service accruals don't stop, then remove both events from the service event history. They are extra which interferes with your understanding of what events are actually impacting the service calculation.
  • If service accruals don't stop immediately (maybe the continue for a year or 2, or just enough to complete a year of service), then remove both events and replace them with a single stop event that accurately defines when service stops (e.g., 2 years later, but no after the next stop event, only if you return to work within 2 years, ...)
• If certain event combinations occur, drop both events, drop one event, drop both events and replace with a single event, ...
  • A stop event is immediately followed by a start event with a year/months/days, then remove both the stop and start events.
  • A particular stop event occurs, but service continues until the earlier of 2 years and the next stop event (may or may not be contingent on returning to work within those 2 years)
  • What if you terminate 7/16/2015 and return to work the following day, 7/17/2015?
• There are sometimes when consecutive start dates or consecutive stop dates are necessary, but it's unusual. For example, layoff then termination, where elapsed time is calculated during the layoff period because hours are not earned/reported then. These situations can make working with events in expressions harder and more complicated. But, it's good to know that the Service Definition with an Event Definition can handle most of these situations.

Following these considerations, below is an example of events stored in a database before a cleanup effort and the service events used in a calculation.  You can see how much easier it is to review and process these events.