The compare option
creates a worksheet with the same name as the forecast. The
results for a simulated example are shown below with both moving
average and regression forecasts. This particular data had
a trend in the mean demand with a value of 1.
As expected the regression forecast does much better at estimating
the future because it includes a trend estimate. The error
for the moving average has a positive bias because the estimate
always lags behind the data. The estimate for the trend for
the regression forecast varies about its true value of 1 and
the mean error is small.