A Control Chart can show the cycle time or lead time for your product, version or sprint. The horizontal x-axis in a Control Chart indicates time, and the vertical y-axis indicates the number of days issues have spent in those statuses.
A Control Chart helps you identify whether data from the current sprint can be used to determine future performance. The less variance in the cycle time of an issue, the higher the confidence in using the mean (or median) as an indication of future performance.
See Viewing the Control Chart.