Data Window
By default, the reports will take into account all the data that has been collected under your account. However, in most cases, running the report on the entire data-set is not needed. It makes sense to generate the report only on the data collected say in the last three months or so.
In cases where you only want to see the open-ended comments for a particular survey or simply see the scores generated in the last week, you can shorten the Data Window to be 1 week.