Optimizer statistics advisor is a built-in diagnostic tool that allows to manage statistics.
The goal of this advisor is
Reviewing the process of gathering statistics
Validation of the quality of existing statistics
Checking the status of auto stats gathering
The statistics advisor checks a set of rules against the data found in the data dictionary. Rules that are violated (or «broken») result in a findings and recommendations.
The recommendations can then be turned into actions (for example an SQL script) which fix the broken rules.