Optimizing parameters includes, during a time interval, rotating from setting a first parameter to a first value for a first time period, to setting the first parameter to a second value for a second time period such that the time interval includes multiple first time periods in which the first parameter is set to the first value sequenced with multiple second time periods in which the first parameter is set to the second value; obtaining, for the time interval, a first set of ratings corresponding to the first time periods and a second set of ratings corresponding to the second time periods; averaging, for the time interval, the first set of ratings to a first average rating and the second set of ratings to a second average rating; and correlating the first average rating to the first value and the second average rating to the second value.