We are comparing the drugs together on their level of effectiveness to assess which treatment is better on each priority. Certainty refers to how confident we are with the results. Things that affect our confidence include how statistically precise our results are, as well as the quality of the trials included in the analysis. Within each priority, the difference between two drugs is classified from best to worst as: a lot better, moderately better, slightly better, slightly worse, moderately worse and a lot worse.