As my MBA courses do a number on my psyche and mental stability, I can’t help but think of everything in the form of business! “They” even turned Starcraft II into supply chain management (I won’t go into the gory details). As such, I’ve calculated the average rate of return for all NL East teams over the past 10 and 20 years. To do this, first I listed the number of wins for the past 20 seasons (’94 interpolated), then calculated the percentage increase or decrease for each season from the season before. Just average these changes together, and you come up with a number representing how we can expect each team to fare in a following season, on average. I’ve converted the final percentages into wins (multiply by 162), to make it all much more palatable to the mind.
Again, in simpler terms, these numbers are the average change in number of wins one can reasonably expect from a team from season to season. The 20-year and 10-year versions are just using those respective data sets (’89-’09 and ’99-’09).
What does this mean? Using the last 20 years as a data source, a Mets fan can expect the team to stay stagnant on average from season to season. Using the past 10 years, we can expect the team to lose an average of 4 wins per season. The Mets are tied for the worst ARoR in the 20-year period and are the worst, by 2 wins, in the 10-year period.
Disclaimer: this technically isn’t an “average rate of return”, but it’s the same formula, and I couldn’t come up with a better term for it!