The formula also takes into account the following factors:. The capture method in Generation I differs significantly from those of later generations. It will give results which are too high if the catch rates are more than this; however it remains a useful approximation as has been verified by using a simulation of the capture algorithm. The capture algorithms in Generation II and onwards have three essential components: the modified catch rate, the "shake probability", and the "shake checks". Generation II handles shake checks slightly differently than the later generations.