I would disagree on this one. I actually tried the report and it does not produce the expected results. I initially thought the answer below to be correct and i also found the supporting elements.1. Report based on a reporting snapshot that runs daily at 5:00 p.m. If you google salesforce analytics overview cheatsheet pdf you will find a document, go to theSection on reporting snapshot and read: "For example, a customer support manager could set up a reporting snapshot that reports on the open cases assigned to his or her team everyday at 5:00 PM, and store that data in a custom object to build a history on open cases from which he or she could spot trends via reports. Then the customer support manager could report on point-in-time or trend data stored in the custom object and use the report as a source for a dashboard component."