The NBA Playoffs start Saturday and a popular form of betting them is using the Zigzag Theory. But is the Zigzag Theory a fallacy or does it really work?
The 2015 NBA Playoffs begin this Saturday, and as usual we will be here throughout the post-season with our NBA picks. However, for those without the inclination or desire to handicap every playoff game, one “lazy” approach that has been popular over the years has been the Zigzag Theory, which merely says to play on the team that lost the previous game straight up in each series.
One obvious drawback of this theory is that you would never bet the opening game of each series, and more than a few action junkies find that hard to swallow at the very opening of the playoffs with eight Game 1s slated for Saturday and Sunday. However, there will be plenty of action to satisfy their thirsts for the remainder of the playoffs with plays on every subsequent post-season game except for Game 1 of each new series. But does it really work?
Well, based on the literal translation of betting every single team that lost it prior game in every single series, that answer would be no, not well enough, at least over the last 14 years. You see, if the Zigzag theory is applied to every applicable game (i.e., non-Game 1s) of every playoff game since 2001, the record betting on all teams that lost the previous game outright stands at 469-446-31, 51.3 percent ATS, not nearly enough to turn a profit at -110 odds.
If you are able to get -105 odds on all of your plays as is more commonly available right now, then that 51.3 percent mark is just about at the exact break-even point and would not be worth your while. However, the fact that the entire population of plays is over 50 percent ATS does seem like a nice starting point that can be made profitable by adding a couple of filters.
And if you simply retrain from playing the Zigzag Theory unless the team you are playing on is currently at home, that already improves the record to 260-238-20, 52.2 percent ATS since 2001. That is not quite at the break-even point at -110 odds of 52.3 percent, but again it is a step in the right direction and it is a percentage that actually yields a profit just standing alone if you get -105 odds.
But why settle for a small profit at odds that you may or may not have available when the winning percentage can be improved on further with just a couple of more easy filters?
Zigzag by Seed
First of all, there is a reason that there are more sweeps in the first round than in all subsequent rounds and that is obviously due to there being more mismatches in the opening round. Granted last season was an anomaly with only two of the eight first-round series being “short” as the Miami Heat swept four games from the then Charlotte Bobcats and the Washington Wizards upset the Chicago Bulls in five games.
The was more of the exception than the rule though as the Zigzag does not usually fare well in the first round with uppers seeds more likely to win consecutive games over sometimes outclassed opponents. Thus we decided to add a filter by only using the Zigzag Theory with top-four seeds.
Here are the Zigzag results for each individual top-four seed for all non-Game 1s for every round since 2001, whether it be at home or away:
1-Seed: 78-82-3, 48.8% ATS
2-Seed: 89-66-6, 57.4% ATS
3-Seed: 65-63-3, 50.8% ATS
4-Seed: 64-51-5, 55.7% ATS
Total: 296-262-17, 53.0% ATS
So just using top-four seeds raises the Zigzag percentage to 53.0 percent, which is now good enough to turn a profit at -110 odds but not as high a percentage as we would like. The breakdown by seed is certainly interesting with the 2-seeds having the best overall Zigzag mark, which bodes well for the second seeded Cleveland Cavaliers and Houston Rockets this season, and the four-seeds also have an excellent record while the one-seeds have a losing ATS mark!
Zigzag by Seed at Home
Now, remember what we said earlier about how simply being at home raised the overall Zigzag records? Well, we thus decided to again do an analysis of the top-four teams only, but this time only if they were playing at home. And lo and behold, the improvement then reached very playable levels on the blind!
Here again are the Zigzag results for each individual top-four seed for all non-Game 1s for every round since 2001, except this time when playing at home only:
1-Seed: 42-40-2, 51.2% ATS
2-Seed: 46-28-3, 62.2% ATS
3-Seed: 38-34-1, 52.8% ATS
4-Seed: 32-25-5, 56.1% ATS
Total: 158-127-11, 55.4% ATS
Now we are getting somewhere as simply playing the Zigzag only with top-four seeds playing at home has produced a nice 55.4 percent win rate over a decent sampling over the last 14 years. Also note that every individual top-four seed did better at home than overall ATS during the course of the study, although ironically only the one-seeds have not been profitable at -110 odds.
Thus it will be interesting to see how the top seeded Golden State Warriors and Atlanta Hawks fare this year.
Top-Four Seed Zigzag by Round
Next we decided to do a breakdown of the top-four seeds by individual round to see if we can find any patterns that could help up strengthen this Zigzag angle even more. And when we did so, we did discover something quite interesting.
Here are the Zigzag results for all top-four seeds broken up by each individual round, whether they be playing at home or away:
First Round: 101-83-8, 54.9% ATS
Conference Semifinals: 96-85-7, 53.0% ATS
Conference Finals: 70-61-0, 53.4% ATS
NBA Finals: 29-33-2, 46.8% ATS
Total: 296-262-17, 53.0% ATS
We found it extremely interesting that the Zigzag turned a profit over the first three rounds but then had a losing record in the NBA Finals the last 14 playoff seasons! And the San Antonio Spurs requiring only five games to win the championship over the Heat last year did not help the Zigzag record of the finals.
Top-Four Seed Zigzag by Round at Home
So that gave us the idea to just use the Zigzag in the first three rounds only, but before making a definitive decision on that, we again took a look at the results by round but for home games only, as those seem to be producing the best results regardless of how we break the Zigzag down.
Here again are the Zigzag results for all top-four seeds broken up by each individual round, but this time only when playing at home:
First Round: 56-38-4, 59.6% ATS
Conference Semifinals: 54-42-5, 56.3% ATS
Conference Finals: 37-31-0, 54.4% ATS
NBA Finals: 11-16-2, 40.7% ATS
Total: 158-127-11, 55.4% ATS
As we all should have suspected, the records for the first three rounds all improved when using the Zigzag for top-four seeds playing at home only. However, take a look at what happened in the NBA Finals, where home top-four seeds off a loss may actually be considered prime fades if the sample size had been bigger.
Regardless, if we stop after the first three rounds only, the winning percentage is an even 57.0 percent ATS over a sampling of 258 decisions in the last 14 playoffs, which we would all agree looks like a great blind bet if it continues!
So to summarize, instead of taking the Zigzag Theory literally and applying it to all applicable games, our “system” for lack of a better word is to apply the Zigzag Theory only to top-four seeds playing at home following a straight up loss and for the first three rounds of the playoffs only, as this has yielded a record of 147-111-9, 57.0 percent ATS since the 2001 NBA Playoffs.
Then, find the will power to just watch the NBA Finals as a fan with no betting interest, with the possible exception of exploring the possibility of fading top-four seeded home teams off a loss for an anti-Zigzag pattern that seems to be developing the last 14 years.