Codility task library includes tasks of various difficulty levels: Elementary, Easy, Medium and Hard. Before any task gets published and becomes available for you, we need to decide which difficulty level is the most appropriate for it.
To do that, the team that has developed the task analyzes all the points included in it and weighs in on how difficult it can be for the candidates. After the decision has been made, it’s time for beta-testing. Other members of our Engineering team, who weren’t involved into the development of the task, try to solve it. Depending on the results that we get, the difficulty level of the task stays the same as assumed, or is adjusted accordingly.
We understand that some of our easy tasks may seem hard for some candidates, and, vice versa, some medium tasks may turn out to be easier than we predicted. That’s why we review the pass rates of our tasks regularly and adjust their difficulty level, if we deem it necessary. In this case, we inform you about the changes, and, if you’re actively using some task, you can adjust your existing tests appropriately.