Graphic: Premier League best buys

If you had £15 million, what would you buy? You could have a bigger house. With a swimming pool. And a second residence on the beach in the Caribbean. Somewhere nowhere near Michael Winner. Or — how about this — you could buy David Bentley. It’s a dilemma, I know.

Perhaps the Fink Tank can help. With the transfer window open, Dr Ian Graham, Dr Mark Latham and Dr Henry Stott have been looking at how well clubs did during the summer when buying and selling.

Our method is simple. We measure every on-field action of every player. Then we relate those actions to the number of points achieved. Once this has been done, we can simulate the league season so far over and over again. We look at it with each newly transferred player in their new team, then look at the season again with each of these players removed and replaced with an average player.

This tells us how much each player contributes per minute on the pitch compared to an average player. Do they add or subtract? The final step is to adjust for the number of minutes played. After all, a great player who never plays is not much use.

So what did the results tell us? The top transfer involved Mark Schwarzer going from Middlesbrough to Fulham, where he has been a spectacular success. One reason for this is that goalkeepers vary a great deal and it makes a big difference having one who plays well. This also explains one of our more controversial results. The Tottenham Hotspur fans sang for Paul Robinson when Blackburn Rovers visited White Hart Lane, regarding their own Heurelho Gomes as hapless. The fans were dead wrong.

To start off with, they were wrong to want Robinson back. Our ratings found him consistently near the bottom of the pack in previous seasons and we still do. Wonder why Blackburn, with essentially the same defence, are letting in more goals? We regard his ousting as a good bit of business for Tottenham.

It is a mistake to confuse the dramatic nature of the goals that Gomes lets in with the totality of his performance. The Brazil international is not one of the best goalkeepers in the Barclays Premier League and it is possible for Tottenham to do better. But he ranks as a positive transfer.

If money is truly no object, Manchester City should be pleased with Robinho, who is clearly superior to any other outfield player transferred. If the £34.2 million bothers them, though, they may care to reflect that our analysis of the club’s performances shows that they have performed worse as a side when he has been on the pitch.

Robbie Keane’s transfer to Liverpool has been described as a failure. It is true that he is yet to make the same extraordinary contribution that he made to Tottenham. However, he is adding points compared with the average and he is in the top 15, as is Deco at Chelsea. It is hard to determine whether their contributions represent value for money without better individual player-wage data.

Our data does seem to suggest that Bentley, the Tottenham winger, would be poorer value than a new swimming pool. However, all our work shows is how successful the players have been so far, not how good they are. And it analyses them in the position they have been playing, not in the position for which they might be best suited.

For now, you may want the two houses. But with the market as it is, maybe Bentley will prove the better investment.