Makinen: NBA true home and road performance

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I’ve always believed that some of my football analysis is foundational enough that it easily converts to other sports. With that in mind, one of the studies I conduct every year for both NFL and college football is called TRUE HOME AND ROAD FIELD PERFORMANCE. I not only look at which teams have the best performance records in each situation but I also employ a formula that qualifies the effective amount by which teams outplay or are outplayed by their opponents. I call this rating their TRUE home and road field performance level. I then use the results in applying team-specific home and road field ratings to my Power Ratings, Effective Strength indicators and Bettors Ratings that are shared with VSiN readers on a daily basis. Naturally, the same logic can be applied in the NBA as well to judge TRUE HOME AND ROAD COURT PERFORMANCE.

As a bettor, I have always found that one of the most important factors in analyzing teams’ strengths in basketball is determining how much each team should be assigned in their games based on being at home or on the road. There are really only two ways to do this: a standard designation or a team-specific assignment. Obviously, I prefer the latter, as it is my belief that there are specific performance trends that warrant treating each team individually, both from a theoretical and actual numbers standpoint. After all, there are clearly environments that are tougher than others across the league landscape.

 

For those of you who like to keep things simple, you should know that in his latest ratings, Jeff Sagarin proclaims that the average home-court advantage in the NBA is 2.94 points. In studying the numbers over the past 1 1/2 seasons, I have found it to be quite lower, specifically 1.87 points. My own home and road court ratings reflect that number and they are built into the Strength Ratings that you see on VSiN.com in the matchup pages. If you’re wondering why I chose the last year and a half for the duration of the study, recall that the 2020-21 season was heavily affected by arenas closed to spectators, and average attendance was less than 1,000 per game. For 2021-22 and the current season, conditions have returned to pre-COVID-19 standards.

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The way I see it, we almost have to do the team-specific method as bettors because there are many reasons why certain teams have more definitive home-court advantage than others. Among these are crowd capacity/enthusiasm, the quality of the team playing there, the style with which a team plays and even the possible distractions for visiting teams. That last one seems to be a bigger issue in the pros than in college. I’m sure you can think of other factors, but in my experienced opinion, one thing is certain, there is no way that every team’s advantage is the same.

 

 

Judging home-court edges as equal across the board can lead to mistakes and missed opportunities, or even worse, losses. For instance, the amount of variance I assign for the 30 NBA teams is as high as 1.6 points, and for those of you regularly playing the NBA, you know how close the final scores can come to the point spreads, so each point is important.

To determine which teams hold the best TRUE HOME AND ROAD COURT PERFORMANCE in NBA, I have taken the teams’ game logs at home since the start of the 2021-22 season, or essentially the last 1 1/2 seasons, and have compared their own average power rating in those games to their opponents’ average power rating, using my actual logged numbers during that span for every game. This margin would be considered the amount they should have won or lost by when meeting on a neutral court, or the expected margin. I then compared this amount to the actual point differential that the team accumulated in those games. Obviously, the teams that had a greater actual differential than expected differential played the “best” at home or away. For NBA teams, the margins went as high as +6.4 for Memphis to -1.7 for Brooklyn at home and as high as +1.4 for New York to -5.1 for Portland on the road.

Keep in mind that all of these studies include the adjustments I make for injuries and scheduling situations.

Of course, you would not want to assign a home-court edge of 6.4 points to the Grizzlies at home as that could put you in a bind for future games. However, you should respect Memphis any time it plays at home until things change noticeably. Similarly, you wouldn’t want to “discredit” the Nets for playing at home, but considering the Cavaliers have been more than 3.5 points worse than the average home team in recent years, you wouldn’t want to assign a standard NBA home-court advantage number either.

In general, using the average closing line for the last 1 1/2 seasons, it indicates that bookmakers will assign about 2.35 points in an NBA game to a home team. Again, my exact number averaged out to 1.87. However, because the home point spread cover rate on that average -2.35 line has been 50.3%, the number 2.2 seems like a strong number to use as the baseline for my own home and road court average ratings.

One important thing to note, I don’t specifically assign my own home and road court ratings exactly with the order of the True Ratings, as I also give strong consideration to the straight-up and ATS records, as well as the perceived difficulty of playing at a particular venue. That said, teams like Golden State, Phoenix, Philadelphia and Boston also command higher home numbers like Memphis, while teams like Houston, Detroit and San Antonio are assigned the fewest. As far as the road ratings are concerned, Boston, Brooklyn and New York are assigned the most, while Golden State, Portland and Indiana receive the least.

Let’s take a quick look at some of the highlights of the study. At the end, you can find the leaguewide chart for the NBA showing the TRUE home and road court performances I have uncovered as well as their straight-up and against-the-spread records.

NBA Home-Court Performance Study Highlights

–       The team with the highest TRUE home-court performance rating over the last 1 1/2 seasons is Memphis, at +6.4. The Grizzlies would actually have been expected to win their 76 home games in that span by 3.2 PPG if played on a neutral court, yet they are winning them by 9.6 PPG, producing an ADVANTAGE of 6.4 points. New Orleans (+4.4), Golden State (+4.2), Cleveland (+3.9) and Toronto (+3.9) round out the five top home-performing teams.

–       The Warriors actually own the best outright winning percentage of any team at home in this study, having gone 64-18 for 78%. That ranks slightly ahead of Memphis, Phoenix and Milwaukee, all of whom have won more than 70% of their home games since the start of the 2021-22 season. The Bucks have been expected to win by the greatest amount according to oddsmakers and have played to the largest point spreads of any team at -7.2, thus the reason their TRUE rating isn’t as high as the others.

–       Memphis’s 49-27 ATS record during the 1 1/2 years of this study is the league’s best among teams. Golden State at 49-31 ATS and Cleveland at 42-28 ATS are the only other teams better than 60%.

–       Memphis’s 117.8 PPG scored and Cleveland’s 104.2 PPG allowed are the high benchmark scoring figures in home games since 2021-22 beginning of the year (BOY).

NBA Home-Court Performance Study Lowlights

–       The team with the lowest TRUE home-court performance rating over the last 1 1/2 seasons is Brooklyn at -1.7. The Nets would actually have been expected to win their 73 home games in that span by 2.3 PPG if played on a neutral court, but they are winning them by only 0.6 PPG, producing a DISADVANTAGE of 1.7 points. Portland (-0.1) and New York (0) are the other teams without positive ratings.

–       The Rockets actually own the worst outright winning percentage of any team at home in this study, having gone 19-50 for 28%. That ranks below Detroit and San Antonio among teams below 35%. The Rockets and Pistons have been expected to lose by the greatest amounts according to the average point spreads, +5.9 & +5.3 for each, respectively.

–       Brooklyn’s 26-47 ATS record during the 1 1/2 years of this study is easily the league’s worst. New York at 29-42 ATS and Houston at 29-38 ATS are the only other teams at 45% or worse.

–       Orlando’s 108.1 PPG scored and Houston’s 117 PPG allowed are the low benchmark scoring figures in home games since 2021-22 BOY.

NBA Road-Court Performance Study Highlights

–       The team with the highest TRUE home-court performance rating over the last 1 1/2 seasons is New York at +1.4. The Knicks would actually have been expected to win their 70 road games in that span by 0.1 PPG if played on a neutral court, yet they are wining them by 1.5 PPG, meaning being on the road actually benefits them 1.4 PPG. The last time I did this study a few years ago, the top team had a -0.8 TRC rating. Boston (+1.1) and Brooklyn (+0.1) are the other teams in positive territory.

–       The Suns actually own the best outright winning percentage of any team on the road in this study, having gone 46-31 for 60%. That ranks slightly ahead of Philadelphia and Boston of the teams better than 60%. The Celtics have been expected to win by the greatest amount at -2.1, according to those setting the odds, thus the reason their TRUE rating not being as good as the Knicks.

–       Oklahoma City’s 44-24 ATS record during the 1 1/2 years of this study is the league’s best. New York at 42-28 ATS and Boston at 47-32 ATS are the only other teams better than 58%.

–       Minnesota’s 116.4 PPG scored and Boston’s 107.1 PPG allowed set the standards for scoring figures in road games since 2021-22 BOY.

NBA Road-Court Performance Study Lowlights

 –       The team with the worst TRUE road-court performance rating over the last 1 1/2 seasons is Portland at -5.1. The Trail Blazers would actually have been expected to lose their 69 road games in that span by 3.7 PPG if played on a neutral court but are losing them by 8.8 PPG, producing a DISADVANTAGE of 5.1 points. Golden State (-4.4) is the other team with a true road rating worse than -4.0.

–       The Rockets actually own the worst outright winning percentage of any team on the road in this study, having gone 14-57 for 20%. Detroit is the only other team below 25%. The Pistons join the Rockets and Magic as teams expected to lose by the greatest amounts according to the oddsmaker number, each playing as underdogs of +8.5 points or more on average.

–       Three teams share league-worst ATS percentages of 39%, those being Golden State, Atlanta and Portland.

–       Orlando’s 106 PPG scored and Houston’s 119.3 PPG allowed are the low benchmark scoring figures in home games since 2021-22 BOY.

Take a look at the NBA home and road chart and draw your own conclusions.