The National Lottery is one of the UK's biggest FMCG brands. Each year it generates 7.2bn of sales and 1.7bn for 'Good Cause' projects. The main role of Lottery advertising is to maximise the number of players by nudging the population into taking part. In this paper, two econometric models, jointly covering 14 of the 21 years of the Lottery's existence, establish how much Good Cause money can be attributed to the effectiveness of Lottery advertising. The case argues that advertising boosts Lottery sales by an average of 2.5 per cent a year, after netting out media spend. This represents a net return of 5 profit for every 1 invested, and adds up to an estimated 850 million of Good Cause funds that advertising has generated since the Lottery launched.