With the release of the 2021 Hall of Fame ballot earlier this month, our thoughts turned to the institution of the Hall itself, and particularly this question: Are enough players being inducted? Or too many? What is the right number of players to have in the Hall, anyway?
There isn't a correct answer to that, of course. Maybe you're a "Big Hall" person, or maybe you like it to be far more selective. Either approach is fine, but without knowing the historic trends of what share of active players at a given time end up getting in, we're sort of shooting in the dark. If we look back through history, we can see if more recent players are getting in at a higher or lower rate -- which might help us answer whether more or fewer players should be inducted.
There are a few ways to look at this, but to start, we'll take a study that Dave Cameron (then writing for FanGraphs, now special assistant to the GM for the Padres) wrote back in 2013 and updated it seven years later. What Cameron did was to look at Hall of Famers split into decades by birth year, pointing out that, at the time, only two players born after 1960 had been inducted (Roberto Alomar and Barry Larkin). While the definition of a decade is somewhat arbitrary, for consistency's sake, we'll stick with doing it in the "1961-70" fashion, not "1960-69."
We'll update that with seven more years, fix what appears to be a minor mathematical issue with the 2013 study, and we'll come up with this:
Looking at it like this, 1.5% of all players who have ever played -- that's 1.8% of hitters and 1.1% of pitchers -- have entered the Hall of Fame. If you think eternal enshrinement should be reserved for the absolute best of the best, then maybe the top 1 percent or so sounds right. It's certainly an easy number to define as "the cream of the crop," anyway.
You'll also notice a slight downward trend. We'll get back to that.
Comparing this to when Cameron did his work in 2013, we've since seen an additional 15 Hall of Famers who were born between 1961-70, and six more, to date, from 1971-80. That's partially due to the passage of time -- Mariano Rivera, born in 1969 and inducted unanimously in 2019, had only just completed his final season in '13 -- and partially because the writers have alleviated a logjam that came to a head when zero players were inducted in '13. (Thirteen have gone in over the last four years.) It remains possible that the 1960s get another bump this year if Omar Vizquel (born '67) and Curt Schilling (born '66) -- who appear to be the two most likely candidates this year -- are inducted.
That aside, we've set a baseline: 1.5% of all players get into Cooperstown. But let's try this another way, because maybe just looking at the share of Hall of Famers out of "all players" gets skewed over time, as the sheer number of players (mostly pitchers) keeps on skyrocketing, while their share of playing time decreases.