I have heard about some call centers using volume metrics like "true calls per hour" to measure productivity, while...
others use efficiency or availability. Are volume metrics appropriate? Which metrics are the most commonly used and the most effective?
Neither calls per hour or availability are a good indication of productivity. Both metrics can be easily manipulated and do not necessarily measure how productive a customer service representative (CSR) or call center may be. A common trend we see is that call centers are moving away from volume-based metrics and towards true performance-based metrics. A good example of a call center performance metric would be call quality. A particular CSR may take fewer calls, but his or her quality of work and service is very high. As a result, there are fewer call backs, resulting in lower costs. Similarly, a CSR in a sales call center may take fewer calls, but produce a higher sales value. In each case, the true metric of their productivity, quality or sales, is not based on volume.
The most effective call center metrics are the ones that drive your call center activities to match your goals. I would first make sure you know what your goals are -- quality, low cost, customer satisfaction, revenue growth, etc. -- and develop your metrics to meet those goals. Remember, metrics drive performance. Take a look at the Call Center Metrics School to learn more about the top metrics to consider.