The Illinois Powerball has been active in Illinois for only two years and already has a major impact on the revenue of Mega Millions. The impact on Mega Millions sales is a negative impact that was not expected. When the Multi-State Lottery Association and Mega Millions lottery participants agreed to sell Mega Millions and the Powerball games side by side in the collective forty-four state lotteries; they did so with the intention of increasing the sales of each group's respective game. In other words, mega million states thought that by adding Powerball more revenue would occur for each game and Powerball only states thought that by adding Mega Millions more revenue would occur for each game.
Although it would seem to make sense that more sales of each would occur if you sold them side.