Statistical results, such as historical cycle time average, are calculated over time for a specific statistical interval. The interval is a period of time where by all historical data that falls with the time period is used in the calculation. For example, a 1-DAY interval may calculate all historical data for all Mondays, depending upon the user's configuration of the Optimize Analytic Engine. For more information about statistical intervals, see the Administering webMethods Optimize guide.

The Optimize REST API service's statistical interval is determined by the service relative to the input time range parameters. Some services provide an optional input parameter for the statistical interval so the user can choose an interval that is more suitable to their use case. If the service does not provide a statistical interval input parameter, then the service will use a 1-DAY interval for the day relative to the given time range's end time. For example, if the input time range ends on Tuesday, the Tuesday statistical interval will be used. If the user does not include the optional parameter, then a suitable interval will be determined based on the size of the time range.