Count and Percentage Statistics, Passing in the Night

This is a post about Albert Pujols.  In his prime, Albert Pujols was one of the best baseball players of an entire era, a time during which he built the very formidable foundation of what is an obvious Hall of Fame career.  While his decline in production has been the subject of many articles, conversations, analyses and more, he continues to do what Albert Pujols is known to do: play baseball.

Pujols’ combination of immense skills and longevity have enabled him to be a part of, and belong to, rarified company.  At this point in his career, more milestones are being achieved than years are passing by.  In 2017, he became the ninth player to hit 600 home runs.  Last season, he collected his 3000th career hit.  Very recently, he has passed Barry Bonds on the all-time RBI’s list, giving him sole possession of third place.

These accomplishments are incredible ones.  Quite a few really talented people have had the chance to play baseball in the Major Leagues, and being near or at the top of any list is significant, let alone for ubiquitous benchmarks like hits, runs batted in, and home runs.

Here are two very similar looking scatter plots to depict Albert’s ascent.  The first depicts Pujols’ year-by-year career hits total, the second tracks his growing home run count.  Each has been fitted arbitrarily with a linear line to track these progressions.

Those scatter plots tell the story of an incredible career, but the achievements of Albert Pujols in the form of counting statistics more recently have come at a cost.  As he accumulates greater and greater numbers of the aforementioned traditional stats, his percentage statistics suffer and in doing so reflect his mortality.  While counting statistics never are subject to regression and cannot be taken away, percentages more cruelly capture the ball-shaped nature of most players’ careers.

Of course, there are numerous exceptions.  Some players tend to inexplicably play better with age, thus defying those percentage declines.  Adrian Beltre comes to mind.  Most players’ careers end too abruptly to display their mortality in such a way. 

In any event, Pujols’ incredible peaks give way to stark valleys.  From a percentage-based standpoint, he had to come back to earth sometime.  As such, these next three plots depict how his year over year batting average, on-base percentage, and on-base plus slugging.  

The milestones that Albert passes (2,000 RBI club, here he comes) signify the his ever-rising counting stats totals.  But more subtlety his percentage stats decline: his career batting average will soon dip below .300 for good, he might end his career with an OPS below .900, his WAR total might hover around 100 until he hangs up his spikes.  

His career’s latter half thus represents the inverse relationship between percentage and counting stats.  At this point in time, headed in either directions, they might be thought of as two ships, passing in the night.