Here is how the home team has faired in that situation, since 1977: Expectancy: 0.464, 69 games, home team won: 32 times They've won about 46% of the time. Only 69 games in the sample, though, so I'd take that percentage with a grain of salt. Looking at run frequency: http://www.tangotiger.net/RE9902score.html Bases loaded and no out, from 99-02, teams scored over 2 runs about 40% of the time and exactly 2 runs, 21% of the time. The home team wins tied, extra innings games about 52% if the time, so the probability of the home team winning in the above scenario is: 40% + .52 x 21% = 51% Run frequency assumes an average pitcher but down in the 9th, the home team often has to face the closer, which is generally an above average pitcher. I'd adjust that 51% down a bit to compensate. (edit: added text to long link --1992)