For example, an absolute forecast error of 100 results in a larger percentage error when the demand is 200 units than when the demand is 10,000 units. MAPE is the best error measure to use when making comparisons between time series for different SKUs. Looking again at Figure 8.2(b), the percent error in period 2 is 16.22 percent, and MAPE, the average over all 10 periods, is 17.062 percent.