I know I can't average percentages, but can I average percentage differences. For example, I've calculated the Mean Absolute Error (MAE) of two forecasts (same sample sizes) and the percentage difference between the MAEs. This is done for each month in the year.
Can I now calculate the average of the 12 percentage differences?
Here's an example of the results:
MAE (OSM) 0.59 0.30 0.47 MAE (DRP) 0.79 0.77 0.80 Perc. Difference -30% -88% -53%
Would the average percentage difference of three results be -57%?