An IS auditor is reviewing the service management of an outsourced help desk. Which of the following is the BEST indicator of how effectively the service provider is performing this function?

The number of calls worked indicates volume or activity, but not necessarily the quality or effectiveness of the resolution provided.

Call transcript reviews can offer insights into call quality, but they are a sampling method and do not provide an aggregate measure of overall customer satisfaction with the service.

Customer satisfaction ratings directly measure how well the service provider is meeting the needs and expectations of the users it serves, which is the ultimate goal of a help desk function. These ratings provide qualitative feedback on the quality, timeliness, and helpfulness of the support received, making them a direct gauge of effectiveness.

Average ticket age indicates efficiency or backlog, but it doesn't directly measure the quality of the resolution or customer happiness with the service.