NBA Finals History and Why the Lakers Are Not Clear Favorites in 2008

Posted on June 4, 2008 by

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There are two methods we could use to evaluate the participants in the NBA Finals. We could look at how many games each team has won.  Or we could consider each team’s efficiency differential (offensive efficiency minus defensive efficiency). 

Table One: The NBA Finals and Efficiency Differential

Table One considers both perspectives.  And it appears that efficiency differential is the best predictor.

If we look at the 34 NBA Finals that have taken place since 1974 (the first year we can calculate efficiency differential), we see that the eventual NBA champion had the better record 20 times.  The team with the best efficiency differential, though, won the title 24 times.  So it appears – from this simple test – that efficiency differential is the better indicator of team strength.

The Upsets

Although efficiency differential does indicate the winner more often than just won-loss records, it’s not perfect.  Ten different times the NBA Champion had the lesser differential in the regular season.  Here are those ten champions (with the difference in differentials – between the champ and its opponent — reported):

2006: Miami Heat (-2.53) over Dallas Mavericks

2001: LA Lakers (-1.02) over Philadelphia 76ers

1995: Houston Rockets (-4.91) over Orlando Magic

1994: Houston Rockets [-2.88] over New York Knicks

1989: Detroit Pistons (-1.05) over LA Lakers

1982: LA Lakers (-0.96) over Philadelphia 76ers

1979: Seattle Super Sonics (-1.97) over Washington Bullets

1978: Washington Bullets (-0.60) over Seattle Super Sonics

1975: Golden State Warriors (-3.53) over Washington Bullets

1974: Boston (-3.94) over Milwaukee Bucks

Since 1982 the weaker team – in terms of efficiency differential – has only won five times.  In other words, across the last 25 years, efficiency differential has called the champion correctly 80% of the time. 

One should note that three of these times, the weaker team (in terms of efficiency differential) – due to a better won-loss record – had home court advantage in the playoffs.   So these upsets were not surprising.

In sum, over the past 25 years, truly surprising upsets – in terms of efficiency differential – have been rare.

Perhaps Not an Upset

Of course, upsets do happen.  But when we understand efficiency differential we learn that what people think is an upset is not always what it appears to be.

For example, in 2004 the Detroit Pistons defeated the LA Lakers.  The Lakers employed Shaq, Kobe Bryant, Karl Malone, and Gary Payton.  And because the Lakers had the better won-loss record, LA had home-court advantage.

Despite this cast of legends, though, the Pistons took the title in five games.  This was considered a surprise at the time, although efficiency differential indicated the Pistons should have been favored.  Detroit had a differential of 6.41 in 2003-04.  The Lakers – even with the “unstoppable” Kobe Bryant – only had a differential of 4.07.

And then there was the “supposed” upset I discussed last summer.  In 1977 the Portland Trail Blazers – led by Bill Walton – took on the Philadelphia 76ers (led by Dr. J.).  Again the Sixers were the heavy favorites.  In terms of efficiency differential, though, the Blazers mark of 4.96 bested the Sixers mark of 3.5o.  So despite the media’s arguments to the contrary, no one should have been surprised when the Blazers took the title in 1977.

Celtics vs. Lakers

If we listen to the many members of media, the Lakers are the favorites in 2008.  In other words, if Boston wins it will be an upset.

Before we get to this year’s contest, let’s take another look at the past. When we think of Celtics vs. Lakers we often think of Larry Bird and Magic Johnson (unless we are much older and then we think of Bill Russell and Wilt Chamberlain).   Three times Bird’s Celtics faced Magic’s Lakers in the NBA Finals.  In 1984 the Celtics proved victorious. But in 1985 and 1987 the Lakers came out on top.

Here is the efficiency differential story of these match-ups:

1983-84: Boston Celtics (6.27) over the LA Lakers (3.52)

1984-85: LA Lakers (6.90) over the Boston Celtics (6.35)

1986-87: LA Lakers (8.85) over the Boston Celtics (6.50)

In each case the team with the better differential took the title.

And that brings us to the 2008 match-up.  The Celtics in 2007-08 had a differential of 10.95 while the Lakers had a mark of 7.35.  The difference of 3.60 has only been overcome by two teams (Houston in 1995 and Boston in 1974).

So the differential story indicates that the Celtics should be the clear favorites. 

Of course, as I detailed earlier in the week, there are reasons to think the Lakers regular season differential understates the quality of this team.  So maybe the Celtics are not clear favorites.

Although the Celtics may not be clear favorites, there doesn’t appear to be a tremendous amount of objective evidence that says the Lakers should be clear favorites, either.  And yet many members of the media have anointed Kobe and company – a team without home court advantage – as the likely winner of this contest. 

Certainly the Lakers could prove victorious.  But again, I see very little objective and systematic evidence that would make anyone certain this was going to happen.  And yes, I don’t think simply stating that Kobe is “unstoppable” constitutes objective evidence.

– DJ

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Our research on the NBA was summarized HERE.

The Technical Notes at wagesofwins.com provides substantially more information on the published research behind Wins Produced and Win Score

Wins Produced, Win Score, and PAWSmin are also discussed in the following posts:

Simple Models of Player Performance

Wins Produced vs. Win Score

What Wins Produced Says and What It Does Not Say

Introducing PAWSmin — and a Defense of Box Score Statistics

Finally, A Guide to Evaluating Models contains useful hints on how to interpret and evaluate statistical mo