For the 2018 playoffs, I’ve been using data from game results and markets and then filtering to attempt to account for injuries. More details below.

For the 2018 NBA Finals, my model says that Golden State is better than Cleveland by 6.2 points on a neutral court. This leads to the following odds for the series.

Golden State has a 89.6 percent chance of winning the series.

As of Tuesday afternoon on May 29th, 2018, Bookmaker had Golden State -1100 to win the series (Cleveland is +750). This implies a 88.6% chance to win the series for Golden State once you account for the vig.

I’m really surprised the numbers match up so well. The NBA playoffs have been frustrating to predict from a numbers perspective because of injuries and Golden State’s underachieving. Here’s how my model works.

First, I took the game results from the season and kept only games in which teams had all their key players. For example, Golden State had 38 games in which Steph Curry, Klay Thompson, Kevin Durant and Draymond Green all played.

This reduces the set of games, but it gives a better picture of how a team might perform with its top players. It also assumes Cleveland’s Kevin Love will play. With this reduced set of games, I take margin of victory and adjust for schedule with my ranking algorithm.

Second, I take the closing point spreads in the markets since January 1st and perform the same filtering process with top players. I generate market rankings by adjusting these spreads for schedule.

Then I blended these two rankings to give the following rankings of playoff teams. The rating gives an expected margin of victory against an average NBA team on a neutral court.

1. Golden State, 8.89
2. Houston, 8.11
3. Toronto, 4.59
4. Cleveland, 2.72
5. Philadelphia, 2.32
6. Oklahoma City, 2.17
7. Utah, 2.10
8. Boston, 1.44
9. San Antonio, 1.35
10. Minnesota, 1.26
11. Washington, 1.26
12. Portland, 0.79
13. Indiana, 0.70
14. New Orleans, 0.69
15. Milwaukee, 0.28
16. Denver, 0.26
17. Los Angeles Clippers, -0.60
18. Miami, -1.23
19. Charlotte, -1.39
20. Detroit, -1.46
21. Dallas, -2.71
22. Los Angeles Lakers, -3.68
23. Memphis, -4.27
24. New York, -4.51
25. Orlando, -4.73
26. Brooklyn, -5.14
27. Chicago, -5.44
28. Atlanta, -5.50
29. Phoenix, -6.67
30. Sacramento, -7.35

Predicting the 2018 NBA playoffs is a mess. The list of problems starts with these issues:

• Elite players like Steph Curry and Joel Embiid will start the playoffs injured.
• Golden State has not performed up to expectation this season, as their defensive efficiency dropped from 2nd to 11th from 2017 to 2018.
• Kyrie Irving is out for the entire playoffs.

Usually, I take my team rankings that include data from all regular season games and calculate championship probabilities. However, that will not work this season.

Here’s how I approached predicting the 2018 NBA playoffs.

First, I took the game results from the season and kept only games in which teams had all their key players. For example, Golden State had 29 games in which Steph Curry, Klay Thompson, Kevin Durant and Draymond Green all played.

This reduces the set of games, but it gives a better picture of how a team might perform with its top players. These numbers assume Golden State and Philadelphia will have Curry and Embiid respectively. With this reduced set of games, I take margin of victory and adjust for schedule with my ranking algorithm.

Second, I take the closing point spreads in the markets since January 1st and perform the same filtering process with top players. I generate market rankings by adjusting these spreads for schedule.

I decided to focus on the last part of the season to get a more recent picture of team performance. The markets still believe in Golden State, but not as much as in earlier in the season.

Then I blended these two rankings to give the following rankings of playoff teams. The rating gives an expected margin of victory against an average NBA team on a neutral court.

1. Houston, 8.53
2. Golden State, 8.45
3. Toronto, 5.49
4. Oklahoma City, 3.05
5. Cleveland, 2.69
6. Boston, 2.47
7. Utah, 2.46
8. Minnesota, 2.42
9. Philadelphia, 2.05
10. Washington, 1.93
11. San Antonio, 1.79
12. Portland, 1.56
14. Indiana, 0.70
15. New Orleans, 0.57
16. Milwaukee, 0.41
18. Miami, -0.48

This leads to the following championship probabilities for 2018 NBA playoffs.

1. Houston, 39.4%
2. Golden State, 36.5%
3. Toronto, 14.9%
4. Boston, 2.2%
5. Cleveland, 1.9%
6. Philadelphia, 1.6%
7. Oklahoma City, 0.9%
8. Washington, 0.5%
9. Utah, 0.5%
10. Portland, 0.4%
11. Minnesota, 0.3%
12. San Antonio, 0.2%
13. Indiana, 0.2%
14. Milwaukee, 0.2%
15. New Orleans, 0.1%
16. Miami, 0.1%

You can compare the calculations with these implied odds from the markets, taken from Bookmaker on Friday morning, April 13th, 2018.

1. Golden State, 36.6%
2. Houston, 28.9%
3. Cleveland, 10.9%
4. Toronto, 9.1%
5. Philadelphia, 4.8%
6. Oklahoma City, 2.1%
7. Utah, 1.7%
8. Portland, 1.4%
9. San Antonio, 1.2%
10. Boston, 1.0%
11. Indiana, 0.5%
12. Washington, 0.5%
13. Milwaukee, 0.4%
14. Miami, 0.4%
15. Minnesota, 0.3%
16. New Orleans, 0.3%

Houston and Golden State should have the best odds to win the title, and both the calculations and markets agree on this.

My calculations are low on Cleveland. The conventional wisdom is that regular season results don’t matter in predicting how LeBron James will perform in the playoffs. This may or may not be true.

However, LeBron does play almost 4 more minutes per game in the playoffs than in the regular season. This should make Cleveland better in the playoffs. My numbers don’t account for different minute distribution and shows how better models could be built with play by play data.

My calculations are also too high on Boston. I did not exclude games in which Kyrie Irving played in my analysis, so some adjustment should be made for this injury.

Get the game by game predictions each day on the main predictions page.

I strongly like Golden State to win the NBA Finals over Cleveland. Let me back that up with some numbers.

My best NBA projections use rankings that incorporate both scores of games and closing point spreads from the markets. These ensemble rankings rate Golden State 5.3 points better than Cleveland on a neutral court.

I then calculate a series win probability by considering this rating differential and a home court advantage of 4.5 points. This implies a 86.3% win probability for Golden State.

It’s worth breaking down some of the components of these ensemble rankings.

By team rankings that consider all games, Golden State rates 7.1 points better than Cleveland on a neutral court. However, this is a misleading number as teams rest their star players and deal with injuries.

I adjust for these player absences by only considering games in which a team has its top 2 or 3 players. These filtered team rankings make Golden State 4.0 points better than Cleveland, which corresponds to a 80.5% win probability.

I like this number since it closely corresponds with another set of my calculations.

In my market rankings, I take closing lines and adjusting for opposition with my ranking algorithm. The playoffs markets have been distorted by injuries, so I use data from the trade deadline in February until the end of the regular season.

These market rankings make Golden State 4.6 points better than Cleveland on a neutral court. This corresponds to a 83.5% series win probability for the Warriors.

Each of these components gives a win probability for Golden State higher than the 73% implied by the markets (Golden State -270 on Wednesday at Bookmaker). The markets feel like Cleveland and LeBron James can outplay their year long numbers more than Golden State.

I don’t buy it, and it comes down to defense.

In points allowed per possession, Cleveland ranked 21st this season, a poor showing for a championship caliber team. This group is capable of better, as they ranked 10th last season.

However, their defense isn’t nearly as good as that of Golden State, which ranked 2nd this season after 5th last season. It will make the difference in this series, which could be much shorter than anyone expects.

These numbers are based on team rankings that consider game results and markets.

San Antonio vs Golden State

Golden State has a 70.4 percent chance of winning the series.

While I’m posting this with the Warriors up 2-0, this win probability comes from numbers before the start of the series.

Cleveland vs Boston

Boston has a 45.1 percent chance of winning the series.

Boston has home court but is not favored to win the series. My rankings put them 1.3 points worse than Cleveland on a neutral court. Note that this still implies Boston as a favorite on their home court.