There has been considerable change in the lottery sector over the last decade, with various reforms to the sector and strong growth among large Charity Lotteries. Whilst seeing strong overall growth, the National Lottery has seen some dips in its sales and returns made to good causes. Various consultations and inquiries have discussed potential explanations for this, including, changes in the mechanisms of ticket prices, the odds of winning, and the possibility that competition from Charity Lotteries may be a threat to the National Lottery. This report seeks to establish what evidence there is for this last claim, as well as for alternative explanations, and to explore whether it is in fact the case that Charity Lottery fundraising complements National Lottery fundraising rather than being in competition with it.