Compare baseball eras with the denominator in view
Counts reflect opportunities
A season with more teams and more games offers more chances for an event. Raw totals are useful for listing what happened, but comparing how common it was requires the same opportunity unit and a clearly stated season range.
Rules change the sample
Automatic runners in extra innings, intentional-walk rules, scheduling changes, and historical scoring practices affect what can occur and what is measured. A modern-rate view should identify its time window instead of quietly replacing the all-history count.
Rates need complete inputs
Batting average, on-base percentage, slugging, earned-run average, and innings pitched each require their own inputs. Baseball innings use outs: 6.2 means six innings and two outs, not 6.2 decimal innings. Missing historical sacrifice data should not be silently manufactured.
Use comparisons as a starting point
Place the two career or season lines side by side, state their time spans, and inspect the source coverage. A longer career has more chances to accumulate achievements. These tables help research; they do not create a universal ranking of players across eras.
Further reading: StatGami methodology, source coverage and terms, Retrosheet field definitions, and nflverse update schedule.