I have ~ 120 different datasets (different scales, sample size etc) and for each dataset, I predict ONE statistical parameter (doesn't matter what for my question) with different methods. To compare the different methods I use RMSE and MAE across the different datasets. I.e. if $m$ is the method than the RMSE is calculated in the following manner:
$RMSE_m = \sqrt{\frac{1}{n}\sum_{i\in D}(\hat{y}_{im}-y_i)^2}$
where $D$ are the datasets and $n$ the number of datasets. Is this approach suitable to evaluated between different methods $m$ or did I miss something?
Thanks