With two seven inning games already in the books, our dauntless editor asked me to estimate the chances of a no-hitter in a seven inning game. I can give a first-cut at that, but there are a lot of caveats.
First off, using the Retrosheet database (1921-2019) I can look at all 328,844 starting pitcher performances. I can then see how many had given up no hits conditional on having reached a particular inning. When we do this, we get the following table:
| Starting | 328,844 |
| 1 | 132,469 |
| 2 | 55,758 |
| 3 | 26,333 |
| 4 | 10,505 |
| 5 | 4,636 |
| 6 | 2,128 |
The first interesting thing to notice about this table is that each row is pretty close to half the row above it.