This research provides additional insights in to when instrumental variable estimation is a proper method to use when investigating or removing causal effects in randomized experiments. this is done by using instrumental variables on the game Dota 2, in which win-rates of a couple heroes are validated and reviewed to test the effectiveness and usefulness of instrumental variables. The results show mixed signs, for such a complex statistical game with many confounding factors, getting a good variable to work is hard. In the end it is concluded that Dota 2 with its randomized game-mode of single draft is still a too complex experiment to retrieve unbiased results from the instrumental variable estimation method. Therefore it is not advised to use this method in a setting where the environment is is too complex.