BBWAA voters typically expend much brainpower crafting their Hall of Fame ballots, given the intense scrutiny the process draws.
They attack the process from various angles while adhering to diverse criteria. Advanced metrics help them either justify or change their position on players as they pour over the calculations.
Then the analytics community use various formulas to assess voting patterns and project future election results.
In other words, the stat nerds study the work of the stat nerds who study the work of the players they vote for or don't vote for. And they crunch numbers accordingly.