The NBA draft lottery takes place tonight with the Rockets having the worst chances (0.5%) to land the top pick and the right to select Kentucky big man Anthony Davis. At least they have a chance though, it wasn't always that way. Pre-1966 the NBA allowed what they called "Territorial Picks" which allowed teams to take a player from their local area if they forfeited their 1st round pick. One famous territorial pick was Tommy Heinsohn made by the Celtics in 1956; the Celtics won 8 titles during his 9 year career. The NBA eventually realized that system was flawed and went to the also flawed system of a coin-flip between the two worst teams. That practice went on for a couple decades with the Rockets benefiting a couple times (Elvin Hayes and Akeem Olajuwon), but it was scrapped after 1984 because of the feeling that some teams were tanking games for a chance at the coin-flip.
Needing a solution to this problem, the NBA gave birth to the lottery system. The new draft system started off with controversy with some fans and media members believing the first lottery was rigged giving Patrick Ewing to the New York Knicks; better known as the "frozen envelope" theory. In the early days of the lottery (1985-1989), every non-playoff team had an equal chance of gaining the top pick; every pick after that was in reverse order of the regular season win-loss record. In 1990 the NBA changed the lottery to a weighted system giving the team with the worst record, the best chance at getting the top pick. At that time, there were only 11 non-playoff teams and it was weighted by giving the team with the worst record 11 chances out of 66 to get the top pick, the second worst record 10 chances out of 66, etc. This system gave us the only team in lottery history to win the 1st overall pick with the worst odds. In 1993 the Orlando Magic had the best record of the non-playoff teams (41-41) and had only a 1.5% chance of winning the top pick, but shockingly the ping pong balls bounced their way and they won the 1st overall pick. The Magic took Chris Webber, but with Shaquille O'Neal already on the roster, they traded Webber to the Warriors for Anfernee "Penny" Hardaway.
Like they'd done before, the NBA reacted to a surprise result in the lottery by, changing the way the lottery works. This time around, from 1994 on they increased the chances of the 4 worst teams and raised the worst overall team's odds from 16% to 25%. The current lottery works on a system of 1,001 different scenarios. Each scenario has an equal likelihood of happening and the teams with the worst records get more scenarios in their favor of getting the first overall pick. The team with the worst record gets 250 chances at the first overall pick, the 2nd worst gets 199 chances, 3rd worst gets 156 chances, 4th worst 119 chances, and so on. A combination of 4 ping-pong balls is drawn out of the machine (numbered 1-14), and the team assigned to that combination wins the first pick. The process is repeated over again for the 2nd and 3rd spots; picks 4-14 is determined in reverse order of record from the remaining teams.
The Rockets have 5 combinations in their favor out of 1,000 and will either have the 1st (0.5%), 2nd (0.59%), 3rd (0.72%) or 14th overall pick depending on how the ping-pong balls bounce. Overall that gives the Rockets a 1.81% chance of landing a top 3 pick; a 98.19% chance of picking 14th overall. The odds are slimmer than slim, but a few teams have beaten long odds before.
Since the start of the weighted lottery system in 1990, six teams outside of the top five (5 worst records) have won the lottery and the 1st overall pick. The last time the team with the worst record and the most ping-pong balls won the lottery was in 2004; the Orlando Magic took Dwight Howard.
Long-shots to win the 1st pick:
1993 - Orlando Magic - 11th Worst Record
2000 - New Jersey Nets - 7th Worst Record
2005 - Milwaukee Bucks - 6th Worst Record
2007 - Portland Trailblazers - 6th Worst Record
2008 - Chicago Bulls - 9th Worst Record
2011 - Los Angeles Clippers (Owed to Cleveland) - 8th Worst Record
When the Rockets won the top pick and took Yao Ming in 2002, they had the 5th best chance (5th worst record) at 8.9% to win. Looking at the results year by year, the worst teams have not fared well since 2005. It can't be anything other than a fluke, but since 2005 only 1 team in the top four (worst 4 records) has won the #1 overall pick (Clippers in 2009). The weighting system hasn't changed so I don't think it's a legit trend, but for the Rockets sake, at least the top 3 teams aren't winning every year. If the Rockets have a miracle go in their favor and land the top pick, we won't need to talk about them trading for a superstar any longer; Anthony Davis is that player.