One of the most frequently used competition formats in the PBA, and in some amateur scratch leagues, is the stepladder format. Theoretically, it could be used with any number of participants, but the PBA usually narrows its field through other qualifying rounds to five before instituting the stepladder format.
How it Works
In the stepladder format, the lowest ranked bowler goes against the second-lowest ranked bowler. The winner of that match takes on the third-lowest ranked bowler, and so on. So, if you're the #1 seed in a tournament decided by the stepladder format, you only need to win one match, while the #5 seed would have to win four matches.
For this example, let's use five random bowlers and consider a hypothetical tournament. The bowlers, listed in order of their respective rankings through qualifying:
In this scenario, the first match will consist of Jason Belmonte (the #5 seed) and Chris Barnes (the #4 seed). Let's say Belmonte wins. Barnes is eliminated, and Belmonte moves on to face Wes Malott (the #3 seed). Malott wins and moves on to take on Rash (the #2 seed). Malott wins again and makes it to the championship match against O'Neill. The winner of that match wins the championship.
And there it is. The stepladder format. It has its proponents and opponents, as do most scoring systems and competition formats, but it's been a major part of the PBA Tour for a long time.