Grading the (Mock) 2015 NBA Drafts

NBA drafts are usually graded team by team even though it’s probably foolish to grade a teams’ performance for picking guys before they even play a Summer League Minute. However, there is one objective way to evaluate drafts: grade the mock drafts. There are innumerable mock drafts out there, and it’s tough to figure out which ones we should be paying attention to. Still, by analyzing how accurate the mock drafts are at predicting the actual picks, you can get a sense of which ones perform best and how useful these popular mock drafts actually are.

The first method is simply by looking at the number of successful hits. In other words how many selections did a mock peg exactly? I looked at 11 different mock drafts from a variety of websites and individuals; I grabbed that data right before the draft began, too.

Referring to the table below, DraftExpress and Chad Ford, arguably the two most cited mock draft creates, performed the best, but DraftExpress pulled ahead after his last update nailed more players, including a couple second-rounders. Getting a second round pick right in a mock draft is like getting a hole in one — it’s quite rare, as last year there were only two total. DraftExpress was better in the lottery, however, which carries more weight and it’s the part of the draft more people reference. CBS Sports’ Sam Vecenie and NBADraft.net also did pretty well.

Table: 2015 mock draft hits

Sources:

http://insider.espn.go.com/nba/draft/mock/?season=2015&version=8&source=Chad-Ford-Mock-Draft

http://www.draftexpress.com/nba-mock-draft/2015/list/

http://bleacherreport.com/articles/2463840-2015-nba-mock-draft-post-lottery-projections-for-all-30-1st-round-picks/page/32

HoopsHype 2015 Mock Draft

http://www.nbadraft.net/2015mock_draft

http://www.nbadraft.net/nba_mock_drafts/consensus

http://www.sbnation.com/nba/2015/6/25/8842161/nba-mock-draft-2015-final-trades-karl-towns

http://www.cbssports.com/nba/draft/mock-draft

http://www.draftsite.com/nba/mock-draft/2015/

For completeness, I included the mock drafts rated by RMSE (root-mean squared error), so you can compare it to last year’s results. The error is calculated as the difference between where a player was supposed to be selected and where he actually was. (Undrafted players are all given values of 70, or ten spots after the draft ends.) RMSE punishes when a projected selection is way off target pretty severely; DraftExpress and a few others were decimated by picking undrafted players in the first round, while Ford skated away free of harm. The second table below is looking at the absolute error and then dividing that by the draft number, so that getting the first overall pick wrong is much worse than being off by 20 places for a second round player.

Table: 2015 mock draft rated by RMSE error

Looking at the ratings, the “winner” is DraftExpress by a hair over CBS Sports’ Vecenie and Ford. Vecenie was solid overall, but killed everyone with the last 16 picks of the 1st round. NBADraft.net was the only other true competitor, as SBNation didn’t even pick the second round and the others’ ratings were too far off. Since Ford and DraftExpress performed well last year, we can say they deserve their reputations, and their last minute corrections give them a leg up on other mock drafts that are only posted once or update more sporadically.

Table: 2015 mock draft ratings

Overall, DraftExpress probably has the best mock draft because it includes a lot of other information, they update frequently, they usually perform the best during the lottery when it matters more, and it’s not partially hidden behind a pay-wall. They’ve also “won” the mock draft contest two years in a row, although with different rating methods. But Sam Vecenie deserves praise for nailing the draft consistency through both rounds. As NBA fans, we pay an inordinate amount of attention to who will pick whom when all you have to do is wait for the results to roll-out, but it’s good to verify who’s actually doing a good job at this — otherwise we’re just staring at noise.