Metric of the Quarter
Measuring Call Center Forecast Accuracy

By Maggie Klenke

Forecasting is the foundation of the entire workforce management process. If the forecast is accurate, the schedules that match it will plan for the staff to be in the right place at the right time, and the intraday adjustments should be minimal. But when the forecast is off target, even the most carefully created schedules have little chance of success and there is likely to be a more chaotic intraday process. Therefore, taking the time to get the forecast right produces multiple benefits.

Measuring the accuracy of the forecast is a good place to start so that you know how close or far off the target the current process is. The most common way to analyze the accuracy of a forecast is to measure the percent of variation between the forecast and the actual results. It is important to measure the call volume as well as the average handle time accuracy separately so that you can identify any anomalies that occur in each of them. Since one is multiplied by the other to compute the total workload, errors in either have significant effects. However, if you only analyze one or combine them into the workload before your analysis for accuracy, you are likely to find it difficult to find the root cause of any patterns of discrepancy.

The following example shows the forecast call volume for the entire day for each day of the week this call center is open. The actual call volume in also shown along with the percent that the actual varies from the forecast, calculated using the difference between forecast and actual divided by the forecast. (Some analysts prefer to divide by the Actual rather than the Forecast. Either is acceptable as long as you understand what you are measuring and are consistent throughout the analysis.)

Forecast Actual % Variance
Monday 3533 3601 1.9%
Tuesday 2455 2544 3.6%
Wednesday 2611 2723 4.3%
Thursday 2990 3111 4.0%
Friday 2935 3078 4.9%
Saturday 1028 1103 7.3%
Total for Week 15,552 16,160 3.9%