Does Minor League Success Lead to Major League Success?
There seems to be some correlation between minor league success and major league results in the last 15 years. There is a strong correlation between top farm systems and wins at the major league level. As MLB.com notes in their farm system rankings, the last 14 World Series winners were ranked in the top ten within five years of their championship seasons. Just like in the Majors, Minor League Baseball has league standings, and team standings fluctuate to an even greater extend because rosters turn over so much. Organizations may quickly promote players, trade some, and cut others. For example, The Baltimore Orioles alone promoted seven prospects after less than one month of the minor league season. To find out whether good minor league teams lead to big league success, I looked at the MiLB standings. The data goes back to 2005, so we will use that as our cut off date. Since MLB protracted the rookie level of the minor leagues this past offseason, I decided to leave that out and only look at the four higher levels. For the sake of simplicity, I am defining good minor league teams as division winners. This is imperfect since each division has a different amount of teams, but it should work for our purposes. The Tables  Well start with the low levels and work our way up. Low-A had four divisions before the reorganization. Since it is far away from the Majors, we will look at Major League teams four and five years after their affiliates won the division. That leaves us with data from 2005-2016. I am using exact numbers to distinguish from playoff appearances within the time frame since those would likely not include players at this level. Plus, I give a two year range for each level to account for how quickly or slowly prospects progress. The bold numbers mean at least one of the playoff teams made the World Series. The only clear conclusion here is that Low-A success means more to Majors in four years than five years. In none of these seasons do three teams make the playoffs five years down the line compared to twice in four years. Plus, only one season leads to a World Series appearance in five years, compared to six appearances in four years, which sounds like a lot to me. The percentage of appearances does not seem to mean much, but the number of World Series appearances sure seems high. Lets move on to High-A, where I am setting the cutoff at three and four years. The level had six divisions before the reorganization. We see again that more World Series teams affiliate won their division in the more recent year, six times three years earlier, and three times four years earlier. It is possible I am setting the number of years too high since I have not looked at any rosters to see where top prospects were assigned. The best ones move quickly through the system, such as Jarred Kelenic playing in AA and AAA before his MLB debut this season. I will circle back to this point at the end, but changing methods in the middle will only confuse the data. Now we are up to AA, where there is a much higher chance that the players at this level will make the major leagues. Because of this, the time frames will be a little more aggressive than the lower levels. There were six divisions in the old AA leagues. I think these are the most confusing results so far. A pretty low percentage of teams made the playoffs, but a high number reached the World Series. In 2005 and 2018, two division winners made the World Series two years later. This is hard to square how there is a low chance of making the playoffs but a pretty good chance of reaching the World Series. You should be skeptical of the 83% numbers from 2018 and 2019, which are dramatically higher than any other season, because 16 teams made the playoffs in 2020, four more than any previous year. Now onto AAA, the closest level to the Majors. We will look at one season later and the same year, given how many prospects are promoted mid-season. There were seven divisions, the most of any minor league level. 2020 is left out since there was no minor league season. Season Playoffs in the Same Year Playoffs in One Year 2005 0% 43% 2006 0% 43% 2007 28% 43% 2008 43% 14% 2009 43% 43% 2010 57% 57% 2011 43% 28% 2012 28% 28% 2013 28% 43% 2014 43% 43% 2015 57% 57% 2016 28% 43% 2017 28% 28% 2018 28% 57% 2019 57% 85%  Except for the first two years at 0%, these are remarkably consistent results. In a plurality of years, three out of seven AAA division winners also made the MLB playoffs that year or the next, and there are plenty of instances where two or four made it. Seven made the World Series in the same year, and eight made the next, the most instances of any level, plus two years where both teams made the Fall Classic the following season (2010 and 2014). Conclusion  Give how much emphasis is placed on farm systems compared to minor league standings, there seems to be a much higher correlation between minor league success and major league success. Of course, there is much overlap given that top prospects help minor league teams win, but lots of these rosters are filled with many players who never make the Majors or only appear fleetingly. Plus, top prospects are not always the difference makers we think there are. Superstars like Juan Soto and Kris Bryant are the more the exception than the rule since most World Series teams are built on veterans compared to rookies. As gratified as I am that minor league results mean something, I am not fully convinced there is as much correlation as the tables suggest. I doubt there is close to a 50/50 chance of making the playoffs in the near future purely because an affiliate won their division. There is some coincidence involved here since only so many teams compete in each division. It is also possible the timeframes are too far away from when prospects actually get promoted and contribute in the Majors. There is certainly room here for more in-depth work. I did not look at any minor league lineups to see when stars played at each level. You could also expand the data to include levels below Low-A. Qualms aside, minor league success is worth paying attention to. If your teams affiliates are playing well, you should feel good about the future.