Trevor Hardy
CFL.ca
You hear it all the time: The CFL season doesn’t really begin until Labour Day: That the pretenders are separated from the contenders after this date and that we don’t truly know a Club’s makeup until they’ve competed down the stretch into October and November.
But what about all those games that take place before that first Monday in September? Could it be that by Labour Day (your team having played approximately half its games by this point) your team has already given you, your fellow fans and management a pretty good indication of what’s to come – good or bad!
The purpose of this column is to understand how well we can predict a CFL club’s eventual post season involvement and success, based on its early season performance. In other words, how likely is your team to experience a taste from the Grey Cup in the same year it starts 0 for July? Conversely, is a club that starts out winning its first six games any more likely to make a long post-season run in November than a Club that has a middling start and then comes on strong in October?
SCOPE OF ANALYSIS
Before we begin, it will probably help if we understand what data was compiled to arrive at our conclusions. A large portion of what you will read here was based on calculating probabilities. And, as you likely know, while the number of CFL clubs making the post-season has remained constant over time, at six, the number of clubs actually competing for those same post season berths has normally varied between eight and nine.
Now, since the basic probability of making the playoffs with eight clubs competing for six spots is greater (75%) than the probability of making the playoffs with nine clubs competing for six spots (67%), I decided to ignore those seasons in which the CFL had nine clubs. That is, for the purpose of this analysis and to maintain consistency and comparability, I have studied those seasons in which eight clubs participated, beginning with the 1988 season.
So, the following analysis has been based upon a total of 112 individual club seasons (14 seasons x eight clubs), representing those from 1988 to 1992 inclusive, 1997 to 2001 inclusive and 2006 to 2009 inclusive.
Alright, let’s get started!
“WE’RE ONLY 6 GAMES IN – IT’S STILL EARLY, ISN’T IT?”
It would appear it gets late awfully early in the CFL! The historical data, presented in Figure 1, suggests that early season performance is a strong indicator of eventual post season participation. What Figure 1 shows us is the historical probability of a club making the post season, given a number of wins after six games.
Remarkably, if your team wins at least 3 of its first 6 games, it is virtually guaranteed to make the CFL Playoffs. This is certainly good news for fans of Montreal and Saskatchewan. Not surprisingly, fans of clubs that can’t muster a single win in the first six games have – historically, at least – been able to start their Christmas shopping early.
“I THINK WE STILL HAVE A SHOT!”
Extending the above analysis to results over the first 12 games might give us a better idea of who the real playoff contenders are. Figure 2 shows us that clubs winning at least six of its first 12 games have, historically, been enough to qualify for a shot at hoisting the Grey Cup.
A slight surprise is that clubs winning only 3 or 4 of its first 12 games still have a chance at making the playoffs. So yes – for those of you asking, wondering and hoping – you do indeed still have a shot.
“YEAH, BUT WHAT ARE OUR CHANCES OF WINNING THE GREY CUP?”
That’s a great question. Of course, no one has a crystal ball, but it sure would be nice if we could tell how likely our team is to win the Grey Cup based on its regular season performance.
Let’s first complete a similar analysis to the one we did above. While we look over these results, remember that it takes three wins (or the equivalent of three wins, counting a first place playoff bye as a “win”) to call yourself Grey Cup champion.
Figures 3, 4 and 5 below show us that there is a definite relationship between regular season success and CFL Playoff glory. Generally speaking, if your team plays well during the season it will tend to perform quite well into the playoffs. For example, if your team has four wins in its first six games, it is expected to win about 1.4 playoff games. (I know that 1.4 wins sounds weird – when I say “expected”, I mean the average number of playoff wins clubs with four wins in their first six games were able to manage based on historical data).
“WHAT’S A BETTER PREDICTOR OF POST SEASON SUCCESS – RECORD AFTER 6 GAMES OR 12?”
Looking at the visual results in Figure 3, Figure 4 and Figure 5 above gives us a pretty good idea that if your team has done well in the regular season, it will typically do quite well in the post season.
But imagine this – your team did really well the first six games, but for some reason, the second six didn’t go so well. Which figure – Figure 3 or Figure 4 – gives us the best prediction of eventual post season success? While the answer to this question may not be so easy to determine from a simple visual inspection of the two graphs, we luckily have a mathematical computation that can tell us which is the best predictor of post season glory. This mathematical computation is called the “correlation coefficient”. But if you want, you can call it the “accuracy of our crystal ball.”
Briefly, correlation is a statistic that measures the linear association between two variables and is measured between negative (-) 1 and positive (+) 1. For example, one would find that smoking and incidents of lung cancer have a high positive correlation, whereas the price of gold and the price of all other stocks have a high negative correlation. Correlation of zero would represent two variables that are not correlated at all.
The correlation coefficient between the number of wins at the six-game mark and the number of playoff wins is 0.227. So, what this means is that there is a moderately noticeable positive correlation between club performance in the first six games of the regular season and the number of post season victories.
The correlation coefficient between the number of wins at the 12-game mark and the number of playoff wins is 0.345. What this tells us is that, yes, a club’s record after 12 games does, indeed, tell us more about how well that team will do in the playoffs.
Finally, I decided to test the correlation coefficient between the number of wins at the 18-game mark and the number of playoff wins. It was calculated to be 0.466, which is greater than both
the 6-game and 12-game calculations above, suggesting – not surprisingly, I suppose – that the way a club plays over an entire season is the best indicator of how well that club does in the post season.
“WHAT IF MY TEAM GETS HOT DOWN THE STRETCH?”
There is a prevailing theory in a lot of professional sports – not just the CFL – that the team that gets hot down the stretch is one that is best positioned to take the championship.
So, I decided to see if this theory is actually true based on the historical evidence available to us. The graphical results are presented below in Figure 6:
Based on Figure 6, it certainly seems like that theory applies in the CFL, too. The correlation coefficient between the number of wins in the last six games of the season and the number of playoff wins is .323.
CONCLUSION
What have we learned from all of this?
1. If your team has a strong start to the season, winning greater than half of its first 6 games, you are likely to be cheering your guys on in the post season.
2. If your team can somehow manage a .500 record through the first 12 games of the season, you are likely to be cheering your guys on in the post season.
3. A good start to the season usually serves as a signal to a strong post season performance. But this signal becomes stronger after 12 games, and even stronger after 18 games, as measured by the correlation coefficients.
4. A strong finish to the season for a playoff bound team serves as a signal to a strong post season, but this signal is not as strong as the one measured by your team’s performance over the entire season, as measured by the correlation coefficients.
5. There is good news for fans of the BC Lions and Edmonton Eskimos in all of this. While both clubs have started the 2010 season with only one win in their first six games – and this definitely hinders each team’s odds of making the post season – they still have a chance. Because history has shown us that these two teams only need to win 4 of their next 6 games to increase the probability of getting into the playoffs from 20% to 80%.
