Examining the MLS Draft: Part 2 - MLS Draft Success Rates
Notes: Part 1 of this analysis (boring descriptive methodology stuff) can be found here. Part 3, in which DC United is examined closely, will be posted later.
MLS Draft Picks: Summary Data
Below is a quick summary showing the various games played statistics, by draft round, for all MLS college/Superdrafts since 1999. There's some interesting analysis to be had in here, but below are some raw numbers as a basis
The 1999 college draft only had three rounds, that's why you see a drop in the overall number of picks for that round. Additionally, in that year, the LA Galaxy chose to pass on their third round pick.
What I find useful about the chart above is that it gives you some quick eyeball measures for how successful a draft pick is overall, and the relative values between rounds. First, note the high rate of failure overall: one-third of the picks will never play a game, and nearly half will play less then ten games. Still, that shouldn't be surprising, as I imagine most drafts in US professional sports show a similar or higher attrition rate. However, the value of a pick does appear to be somewhat dependent on the round in which it occurs. The chart below shows the relative success rates, by percentage, of draft picks based on each round:
Note that 56% of first round picks see at least around 2 seasons of work, and 76% get at least one season. The second round also sees some contribution, with about 42% of the picks getting at least one season, and 65% seeing at least a portion of a season. Rounds 3 and 4 are pretty much identical: A small portion of players (less than 20%) making contributions over multiple seasons, while the vast majority of players (about 80%) never quite get a full season's worth of work.
A phrase that is thrown around a great deal is a "bust". Based on this data, I think it is fair to say that any draft pick that doesn't see at least 10 games can not be considered a decent draft pick. I like this number since it allows us to look at drafts across time (Since it can be accomplished in a single season), and determine how well the different draft classes. The graphic below, based on this fairly low definition of success, shows the success rate over time in all rounds.
2006's data may be artificially low since draft picks haven't really had time to get acclimated to the game yet, but I'd say that it's fair to say that 55% of a team's draft picks should see at least 10 games. Note that at least 45% will see less than that, but that number seems a fair baseline across time.
The key finding here is that draft picks will see an incredibly high attrition rate. Just over a third will see at least a season's worth of work. That being said, you should be able to better in the first and second rounds. The third and fourth rounds are pretty much a crap shoot and interchangeable. Still, I think we have enough to set expectations, by round, for your picks. First round picks should last you a few years. Second round picks around one year. If you can get anything out of third and fourth round picks, you're ahead of the game. In my mind, a first round pick is about three times as valuable as a second round pick, and a second round pick about twice as valuable as a third or fourth round pick (this makes a first round pick about six times as valuable as a third or fourth round pick). Third and fourth round picks are pretty much interchangeable. That being said, even among first round picks, about one-quarter won't pay off into a full season's worth of work.
Given that each team will have about four draft picks a year, it seems clear to me that rebuilding through the draft is a difficult proposition. I also want to stress that our baseline for success is fairly low: Just making it into games. If you're looking for star players around which to build a team, you probably won't find it easy going in the draft.