How often does a bases loaded no out situation end with 0 runs?

This idea started as a conversation on Twitter about having the bases loaded with no outs but failing to score a run:

Can you tell if that’s gone up in recent years by only checking older data? I thought it was a time-honored truth that it was like 9–10% of the time

— Andy (@andyswaff) August 19, 2020

Honestly I was pretty surprised – 16% sounds a bit high to me. But I was also curious about what Andy asked. My hypothesis was that it would be going up in recent years since the strikeout rate has been going up (which is very helpful in getting out of these situations!), but the handy baseball win expectancy finder didn’t have run expectancy data by year.

So after a bit of coding I added that to the site, and ran an analysis. And here are the results: (raw data in this Excel file)

I added a rolling average (the blue line) because this only happens ~600 times a year so the data is rather noisy. Anyway, the percentage has indeed been going up lately, although it was even higher in the 1960s when total offense was down. The minimum percentage is 12% in 1994 (in the steroid era), and the maximum percentage is 20.5% in 1967 (right before the Year of the Pitcher!)

More articles written with data from the Baseball Win Expectancy Finder:

• How common are walk-off walks (on four pitches!) in baseball?
• How likely are walks and strikeouts by count?
• How unlikely are two immaculate innings in the same game against the same batters? (very!)
• Why are so many runs scored in the bottom of the first inning?
• Did the Astros set a record by challenging a play while up 13 runs? (no)
• Does the length of the top of the first inning affect the number of runs scored in the bottom of the first? (somewhat!)
• How effective are teams at manufacturing runs?