The NBA’s draft lottery, which takes place annually between the end of the regular season and the draft, is the league’s way of determining the draft order and disincentivizing second-half tanking. The lottery gives each of the 14 non-playoff teams – or whichever clubs hold those teams’ first-round picks – a chance to land one of the top four selections in the draft.
Although the top four picks of each draft are up for grabs via the lottery, the remaining order is determined by record, worst to best. The league’s worst team isn’t guaranteed a top-four spot in the draft, but is tied for the best chance to land the first overall pick and will receive the fifth overall selection at worst.
The first four picks are determined by a draw of ping-pong balls numbered 1 through 14. Four balls are drawn, resulting in a total of 1,001 possible outcomes. 1,000 of those outcomes are assigned to the 14-non playoff teams — for instance, if balls numbered 4, 7, 8, and 13 were chosen, that combination would belong to one of the 14 lottery teams. The 1,001st combination remains unassigned, and a re-draw would occur if it were ever selected.
The team whose combination is drawn first receives the number one overall pick, and the process is repeated to determine picks two, three, and four. The 14 teams involved in the draft lottery are all assigned a specific number of combinations, as follows (worst to best):
- 140 combinations, 14.0% chance of receiving the first overall pick
- 140 combinations, 14.0%
- 140 combinations, 14.0%
- 125 combinations, 12.5%
- 105 combinations, 10.5%
- 90 combinations, 9.0%
- 75 combinations, 7.5%
- 60 combinations, 6.0%
- 45 combinations, 4.5%
- 30 combinations, 3.0%
- 20 combinations, 2.0%
- 15 combinations, 1.5%
- 10 combinations, 1.0%
- 5 combinations, 0.5%
If two lottery teams finish the season with identical records, each team receives an equal chance at a top-four pick by averaging the total amount of outcomes for their two positions. For instance, if two teams tie for the league’s fourth-worst record, each club would receive 115 combinations and an 11.5% chance at the first overall pick — an average of the 125 and 105 combinations that the fourth- and fifth-worst teams receive.
If the average amount of combinations for two positions isn’t a whole number, a coin flip determines which team receives the extra combination. For example, if two clubs tied for the league’s third-worst record, the team that wins the coin flip would receive 133 of 1,000 chances at the first overall pick, while the loser would receive 132. The coin flip also determines which team will draft higher in the event that neither club earns a top-four pick.
The table below displays the odds for each lottery team, rounded to one decimal place. Seeds are listed in the left column, while the picks are noted along the top row. For our purposes, the first seed is the NBA’s worst team.
It’s worth noting that the NBA’s lottery format was changed in 2019, with that year’s draft representing the first one that used the new system. Previously, only the top three spots were determined via the lottery and the odds were weighted more in favor of the league’s worst teams.
The odds-smoothing effects of the new system were felt immediately. The Pelicans, Grizzlies, and Lakers – who claimed the Nos. 1, 2, and 4 picks, respectively, in 2019 – each ranked outside of the top six in the initial lottery standings.
In 2020, the lottery format has been tweaked slightly to account for the fact that the NBA was unable to play out its full regular season. The eight teams that were not invited to Orlando to participate in the resumption of the season will receive the top eight spots in the lottery standings. The final six spots will go to the six clubs that don’t make the postseason in Orlando, sorted by their records through March 11.
We previously broke down what the 2020 lottery odds will look like if the Nets, Magic, and Grizzlies all hang onto their playoff spots. This year’s event has been postponed until August 25.
Note: This is a Hoops Rumors Glossary entry. Our glossary posts will explain specific rules relating to trades, free agency, or other aspects of the NBA’s Collective Bargaining Agreement. Information from Tankathon.com and Wikipedia was used in the creation of this post.
Earlier versions of this post were published in 2012, 2013, and 2019.