A method for awarding a jackpot, and a corresponding gaming machine and system. The jackpot is awarded based upon a presence of scatter symbols appearing in a game outcome in a predefined manner. The jackpot is preferably linked across multiple machines. In a preferred form, scatter symbols on one reel may be in an active or inactive state, the jackpot is awarded only if they are in the active state, and the probability of them being in an active state is dependent upon the size of the player's wager, so as to provide linear returns to players.