Click here to see the expected cost of the African Cup of Nations

The African Cup of Nations is the sort of thing pundits love. It means that whenever any non-expert hazards their opinion about the coming season, they can be put back in their box. “Ah, but you are forgetting the African Cup of Nations.”

The conventional wisdom is that the tournament taking place in Ghana is one of the keys to the season – changing the fortunes of the leading clubs and therefore, for instance, the destination of the Barclays Premier League title. The fact that Didier Drogba would be unavailable for at least five games has often been cited as a cloud on Chelsea’s horizon.

I have always been a sceptic. Over a season, an individual player can obviously make a significant difference. But over a few matches? And even if they are really good, people often forget that top clubs have excellent replacements just waiting for their chance.

The best way of settling this, of course, is with the data. Dr Henry Stott and Dr Ian Graham have been looking at the players who are in Africa and working out how much difference their absence will make.

Fink Tank has a player level computer model. It processes every kick by every player and relates their contributions to the number of points teams score. By simulating the Premier League campaign again and again, pulling out individual players and replacing them with an average player in their position, it is possible to work out how many points a player is adding per game compared with the average.

The first point that flies out from this work is how small the numbers are. In terms of points, the most valuable Premier League player in the tournament is Salomon Kalou, of Chelsea, and even he is only adding 0.5 of a point over five games when compared with a player merely of average quality. Sulley Muntari, of Portsmouth, adds 0.4 points, while Yakubu Ayegbeni and Steven Pienaar, of Everton, Michael Essien, Kalou’s Chelsea teammate, and Kolo Touré, of Arsenal, add 0.3 points each. So you can see what I mean – the impact is not big.

You will have noticed a missing player – Drogba. His added points? Zero point zero. Last season he was magnificent, this season less so. Chelsea fans will be surprised to see Kalou rated above Drogba, but this is not an estimation of their basic abilities, merely of their contribution this season. Kalou has done much better on shots on goal and assists and shot assists. Drogba has also been wasteful when passing.

Now comes the most difficult bit of the analysis: estimating who the clubs will play when their stars are missing. So we assume, for instance, that Arsenal play Philippe Senderos when Touré is away. Touré contributes 0.3 points over five matches and Senderos 0.9 points. Thus the African Cup of Nations forces Arsenal into a swap that might add points. Or at least 0.6 of a point.

Chelsea, on the other hand, might be forced to play Steve Sidwell instead of John Obi Mikel. This would lose them 0.7 of a point.

The graphic shows the overall figures. But note these things: that clubs may use different replacements (Michael Ballack, say, not Sidwell) and they may do better (Ballack has not played enough this season to be measured), that player performance varies from period to period, and that the numbers are all so small.

The best advice I can offer? Do not let the African Cup of Nations change your assessment of the season one little bit.

Email: finktank@ thetimes.co.uk