There is nothing more difficult in science than to predict the future, yet that is the ultimate goal of science. Scientists have even gone so far as to mathematically prove that they cannot predict the future just so that they can be frustrated in their attempts to do so.
In the science of basketball, the NBA draft comes around every year to reiterate that, even though we know that "If Michael Jordan, then Championship", no one can predict the NBA future.
There are two basic needs for making predictions: information and the rules to put that information together. In basketball, we rarely have all the information about a player to make a good prediction. Just about everyone but Marty Blake has only the smallest shards of information about the players available to be drafted. No one has all the rules for putting that information together. That would be the stuff of science fiction.
This is an attempt to take the good information that we have on Tim Duncan and put it together with the situation he will be entering in the NBA.
Tim Duncan is the safest bet in the draft, but due to the team he is going to, he is also one of the biggest question marks. Because the San Antonio Spurs appear determined to make him their number one draft pick, Duncan is going to have to coexist as a Twin Tower. Twin Towers are an experiment that has a rather brief and spotty history.
The most prominent set of Towers were Houston's of the mid 1980's, which featured two number one picks in Ralph Sampson and Akeem Olajuwon. Faced with the curse of too much talent at the same position, the Rockets chose to play both Sampson and Olajuwon -- two centers -- at the same time, Sampson as a power forward and Olajuwon as the center. Sampson had struggled as a rookie in '84, lifting the lowly Rockets from the worst team in the league to just the worst team in the west. Sampson won the Rookie of the Year Award, but his rookie impact as a supposed franchise player was smaller than Shaquille O'Neal's, David Robinson's, Larry Bird's, Lew Alcindor's, and ...
Akeem Olajuwon's. Olajuwon joined the Rockets after Sampson's rookie year. The Rockets went from a 29-53 team in '84 to the playoffs in '85 with a 48-34 record. The team improved dramatically both offensively and defensively. The Twin Towers seemed to be working, though questions always surrounded the hype.
In their second year together, the Twin Towers would be in the NBA Finals. A year after that, Sampson would succumb to the first of his major knee problems, missing almost half the season. He would play only 19 games the following year before being traded to the Warriors. The Rockets didn't suffer much when Sampson was injured. They didn't suffer much when they traded him away either.
The other Twin Tower experiment was carried out by the New York Knicks of the mid- to late 1980's, playing Patrick Ewing and Bill Cartwright. Cartwright was never seen as a franchise player, but he was a good offensive player up to this point, one who managed to go to the foul line with a greater frequency than just about anyone in the game today. These Twin Towers coincidentally played only two full seasons together also. An injury to Cartwright in Ewing's rookie season cost them that season. The experiment was ended in 1988 when Cartwright was sent to the Bulls for Charles Oakley.
The Knicks' record over the two full seasons of Twin Towers was 62-102. The Rockets' record over their two seasons of Twin Towers was 99-65. Both teams improved with their Towers over what they had been. Both teams lost nothing when they broke the Towers up.
A general characteristic of centers -- certainly not a universal characteristic -- is that they are more important defensively than offensively. A good center shuts down the interior to easy baskets more than he wins games by scoring. One might think then that two centers are better than one. These two experiences with Twin Towers suggest otherwise.
The following numbers represent the defensive ratings for the Houston Rockets over a seven year period, including the year before Sampson arrived up to his first full year in Golden State. A smaller number indicates a better defense. If two big men are better than one, the more games that both Sampson and Olajuwon play, the lower the defensive rating should be; for instance, this would imply that the 103.1 rating (letter a on the left) below should match up with the number 3, where both Sampson and Olajuwon played 82 games. See if you can match the defensive efficiency with the season on the right, then click below to see the answer.
If you got many of those right, you got lucky. There is no obvious correlation between the number of games played by the big men and the defense, particularly for Sampson.
Actually, Olajuwon's defensive dominance did strangely correspond to the departure of Sampson. The best defensive season of the seven shown above was the one where Olajuwon played a full season and Sampson played in Golden State. Over the next couple seasons, the Rockets' defense would get even better and Olajuwon would garner momentum for the two Defensive Player of the Year Awards that, like most winners, he would win a couple seasons past his best defensive years.
The pattern is not quite as clear for the Knicks, but it is still there. Of the two healthy years for the Towers, one of them was good defensively and one was pretty bad. When Cartwright left, the Knicks were slightly better than average defensively.
Importantly for San Antonio, however, is that neither Houston nor New York had a dominant defense just by having two seven-footers patrolling the paint.
This is just a history lesson and, frankly, I rarely trust history for much. I use it as a guide to learn the real reason, but not as a reason itself. In this case, history suggests that placing two traditional centers on the court and telling them to shut down an opponent may not work as well as advertised. The reason for this may be that a defense is geared to have one big guy guarding the one basket; if there were two baskets to defend, Twin Towers would be awesome. Another reason for this may be that the two teams that tried it didn't try it with very good players.
It would be a very important result to conclude that having two seven footers does not significantly aid a defense. It would change strategy and it would place teams like San Antonio in a tremendous bind, where the value of what they have in that first pick is so much less to them than it is to everyone else. There is not yet enough evidence to conclude this, but there is more than history's suggestion. Centers who are trained to be the last line of defense cannot behave that way if there are two of them on the court. Essentially, they have to behave as though there are two baskets on the court with one defending the right side and the other defending the left. If this is not taught to centers, they don't compliment one another by rebounding the miss the other forced. They don't cut off the pass forced by the other. The defense could actually be worse, just as it apparently was in Houston with their Towers...
Or it could be that Sampson was bad. Sampson never did develop as a pro. His numbers in the NBA, both offensively and defensively, were mediocre. The player today who best matches Sampson is Vlade Divac and Divac actually looks a little better. But -- San Antonio would like to know -- was there any way to predict that Sampson would fail based on his college experience?
Remember the first paragraph: There is nothing more difficult than to predict the future. Sampson was seen by everyone as a franchise player. It was reported that Houston tanked games in order to draft him number 1. The numbers, which don't suffer from biased media coverage, show only one flaw in Sampson's college game: