Having worked in phone support I can tell you what this actually means. We were ranked according to three metrics: productivity (calls per hour), customer satisfaction (% of surveys responded to with satisfied or very satisfied post call), and quality (periodic random checks of calls we took where you got a % score and various demerits subtracted from it if you did or didn't do certain things, like all the crap they make you say at the end of the call).

Higher ranking in those got you the choice of better shifts and slightly higher raises (maybe), and there were minimums to hit in each.

So yeah, that message means they're probably using random calls to do QA checks on their employees.