Monday, January 4, 2016

Big-Win Percentage: A Comparison of Celtic Managers (2000-Present)

According to The Numbers Game by Anderson and Sally, because of the inherent randomness of football, "unless a match ends with a three- or four-goal victory, it is very hard to be sure whether the better team won" (this claim is based on research by Skinner and Freeman published in 2009).

With this idea in mind, I thought it would be interesting to look at the Big-Win Percentage (BWP) of Celtic managers domestically since the 2000-01 season (including the current season). I defined BWP as the percentage of matches won by 3 or more goals. The results are summarized in Figures 1 and 2.



Celtic's BWP at home since 2000 is 33% (Figure 1) versus 22% away (Figure 2). 

It may come as a surprise to some Celtic fans that current manager Ronny Deila has the best home BWP of any recent manager. In contrast, Neil Lennon and Martin O'Neill are tied for the best away BWP.

One thing to keep in mind about these numbers is that they do not necessarily correlate with the style of play. To illustrate this point, I calculated the home and away BWP for Tommy Burns' tenure as Celtic manager (1994-1997).

The style of play under Burns is often remembered fondly as free-flowing, attacking, and highly entertaining, the antithesis of Deila's style some would say. Yet, Burns' home BWP was only 26%, and his away BWP was even worse at 6%. Both of these numbers are far worse than Deila's.

Obviously, Celtic fans have a broader view of what counts as attractive football. It's not just about the goals.