What Insights Are You Missing When You Only Look at Call Data?

Call data gives us useful information where calls came from, how many were generated, how long they lasted, and when they occurred.

But I wonder how much context we miss when we rely too heavily on those numbers.

A longer call isn't necessarily a better call, and a call that looks positive in the data may not lead to a meaningful outcome. Sometimes the more useful insight is in what happened during the conversation and what happened afterward.

For those working with pay-per-call campaigns, what information do you look at beyond basic call data, and what have you found most useful?