What Leads To Baseball Teams Postseason Success?

This is the question I pondered as I constructed my Data Visualization Final project. Using the built-in R Lahman package, I looked at five different factors to answer this question. Additionally, I looked at how these factors have changed over the different eras of baseball and how the factors are different in the regular and postseason. The five factors I chose were Salary, ERA (Earned Run Average), BA with RISP (Batting Average with Runners in Scoring Position), Starting Pitcher Innings per Game, and Home Runs per Game. Here is what each factor showed:

This graph displays teams' salaries over the years and each team's success. The blue line represents the mean salary for each respective year. The mean over the years has dramatically increased, and the disparity in team salaries has increased. This increase in spending is due to teams having higher TV revenue and the disparity is due to more teams in smaller markets and no salary cap or floor, unlike other sports. Before the 2000s, having a higher salary than the mean would help your chances of making the playoffs and winning the World Series. Though in the 2000s as the years have gone on having a higher salary than the mean has helped less and less and nowadays almost always guarantees nothing. In fact, in 2008, 2013, and 2016 the teams with the highest salaries in the league didn't make the playoffs altogether. This results from there being more postseason spots and also highlights the randomness of the sport. Although baseball may seem like you can pay to win that is not true as salary is only a minor piece of the postseason success puzzle if at all.

This graph shows both the regular season and postseason ERA of each postseason team's ERA in 2022. ERA is the amount of earned runs that a pitcher gives up per every 9 innings they pitch. This graph also shows success as the x-axis is organized by increasing postseason success where TBR was eliminated first and HOU won the World Series. There are outliers present in both the regular and postseason but they are more common in the regular season. These outliers occur from a pitcher having little success in their few opportunities. Teams’ having low median postseason ERAs doesn't guarantee success as TBR had a really low median and still got eliminated in the first round. This is due to their team not scoring more runs than they allowed and the small sample size of the team only playing in two games. Additionally, most teams' median ERA drops in the postseason and only correlates to teams not having success if it increases. This is shown with LAD and ATL who have higher median postseason ERAs than in the regular season. Both these teams had byes so they didn't play in the first round but they lost the first series in which they played. On top of the higher median ERAs in the postseason, we can also state that high ERAs in the postseason generally lead to little success. Meanwhile, for low median postseason ERAs, we must look at other factors.

This graph portrays the percent change between BA with RISP in the regular and postseason in 2022 and the teams' success. Batting Average with RISP is the amount of hits a teams get per at-bat when there is a runner on second and/or third base. Most of the teams faced a decrease in their BA with RISP as teams have greater pressure and face harder pitchers in these scenarios. There are some increases but one would expect these to not be sustained if these teams got more games. Just like the ERA graph having success in a sample size with BA with RISP helps but guarantees nothing. With TOR they had good BA with RISP in two games but their pitching didn't hold on as in one of the games they lost 10-9. This also occurs on the large percent decrease size with TBR as with such great pitching they still lost hit at all in these scenarios. Meanwhile, the teams in the middle of this graph were able both to pitch and hit which is the name of the game and allowed them to succeed. So having a good BA with RISP doesn’t guarantee anything but not having a good BA with RISP will lead to little success.

This graph exhibits the difference in starting pitcher innings per game for postseason teams in the regular and postseason and in 2012 and 2022. The decimal in the average starting pitcher innings per game represents the number of outs (6.1 means 6 innings and 1 out). In 2012 only one team had starting pitchers averaging 5.2-6 in the regular season meanwhile in 2022 more than half of the teams were in this range. This also occurs in the postseason with 2012 having 2 in the 3.1-5 range while more than half are in that range in 2022. One may think this is due to the invention of the opener (a relief pitcher starts the game and pitches 1 or 2 innings) but the data set doesn't include them so they don't skew the results. Instead, this is due to teams being protective of starting pitchers and teams changing their philosophy. This philosophy is that teams believe that their relief pitcher has a better shot at getting a batter out than a starting pitcher who would face the same hitter for the third time. This philosophy shift is applied more extremely in the postseason with most of the teams' averages either staying the same or dropping 1-3 ranges. This happens because each game means more so the teams are willing to do whatever it takes to win and most teams believe they have a better shot if they pull their starting pitcher earlier. Although this doesn't answer the main question at hand it is fascinating to see how quickly things can change in baseball in just ten years.

These graphs display two different relationships. The top graph displays the average HRs per game for all of MLB from 1962 to 2022. The graph displays the exact HRs per game number when the cursor is highlighted over it. The bottom graph then shows the teams that made the postseason in the highlighted year their success and each teams’ HRs per game in the postseason. The HRs per game in the regular season stayed pretty consistent until 1994 (most of the major drops are due to strikes like 1981). After 1994, baseball entered the steroid era which led to a dramatic increase in HRs per game. Even after the steroid era ended, the number of HRs per game didn't drop to pre-steroid era levels as home runs were now thoroughly entrenched into the heart of the game. The only outlier after this point were 2019 due to the ball being juiced allowing for more home runs and 2020 since the season was only 60 games. For the postseason having more home runs per game had less of an effect before 1969 as you only had to win 4 games to win the World Series. Though after 1969 they added the Championship Series teams needed to win 8 games to win the World Series. So now hitting more home runs per game would help teams advance further in the postseason. This is not an all-out guarantee but if you don't hit home runs you ain't going to have success.

These trends continued as baseball continued until baseball added the Division Series in 1995 and Wild Game in 2012. The same trend of HRs per game helping teams advance could be seen in some years like 2008 but mostly with the extra games sample size became a factor. So now the teams' HRs per game that are closest to the regular season HRs per game average are the teams with the most success. In 2017 the regular season average was 1.488 and HOU and LAD whose postseason averages are closest to that both made the World Series. So like with the other graphs, you must look at HRs per game with the other factors to see the full picture.

When combined these factors play a key role in telling the story of teams' success. However, they do not tell the full story as there are many more factors at play. Additionally, these factors will explain why a team won and won't really be able to help you predict success ahead of the fact. This is due to the one factor that teams must have but can't be controlled or quantified, luck. For that, you just have to have the baseball gods on your side. On top of luck, each factor’s effectiveness changes year to year and constantly evolves as baseball evolves so there will never be an exact science to figuring out success, and that unpredictability is the beauty of sports and baseball.