Is it appropriate to rank effect sizes?

Yes, where it assists in understanding of the underlying story and the many nuances around this story. In Visible Learning (2009), Professor Hattie chose to rank the relative effect sizes of 138 influences that related to student learning and achievement. This list provided a visual presentation of the effect sizes for each influence in order address and understand some of those with low effects (e.g., teacher subject matter knowledge), to understand some that are lower than expected (e.g., class size), and those with much variance (e.g., feedback).