From TMCnet.com, July 23, 2014...

We’re all accustomed (some might say “tired”) of hearing the line that “this call may be recorded for quality monitoring purposes." The disembodied voice says “may be” because many call centers record only a portion of their calls. Inevitably, those recorded calls are being used to sample the quality of employees’ performance. A manager listens, critiques or praises as the case may be, and may even recommend a promotion or a raise. (Or, if the agent’s not so lucky, some remedial training.)  Read more.