Your Castrol EDGE Index questions answered

At UEFA EURO 2012, the Castrol EDGE Index has been using the latest tracking technology to analyse and rank individual displays. Each player's every pass, save, shot and tackle has been measured and as we reach the semi-final stage the top three is made up of Cristiano Ronaldo, Pepe and Claudio Marchisio. With the tournament approaching its conclusion, UEFA.com gave users the chance to tweet their questions about how the Index works and why some players are ranked higher than others.

@Jesse_tb: Why is Andrea Pirlo not in the top ten given his consistent and influential performances?

Castrol: Compare him to the lowest midfielder in the top ten, David Silva, who is seventh. Pirlo's passing has been better − he has completed 282 of 367 attempted (77%), and has forward passing figures of 181/238 (76%). Silva's numbers, on the other hand, are only slightly lower: 157/209 (75%) and 74/109 (68%).

However, what denies Pirlo a top-ten spot is his shooting. In four matches he has scored once but had, in total, only four shots on target, all from long distance. These do not generate much credit. Silva has performed much better, scoring one goal and having five on-target shots from a closer range (distances of 11m, 15m, 16m, 19m, 21m).

@ismailMasoud: How do you calculate a player's game-by-game mark and overall score?

Castrol: A player is awarded points for every action he completes on the pitch. Different actions generate varying amounts of points. For example, a dangerous pass in the opposition's penalty area is more valuable than a backwards one into a player's own half.

Similarly, winning back the ball in the centre of the field is not as valuable as doing so in front of either goal. We also take into account the amount of time each player has appeared for. We penalise players with a low total of minutes in order to avoid, for example, having somebody near the top who has played only one half but managed to score.

@boazmuoga: Why is Cristiano Ronaldo top and not Andrea Pirlo or Bastian Schweinsteiger?

Castrol: Ronaldo is a different type of player − his main responsibility is scoring. The other two players are similar because, besides shooting, their game is defined by high passing activity.

Schweinsteiger, via his passing, has consistently contributed to Germany's attacking efforts, but his four shots on target, all from long distance, haven't given him much credit. Pirlo's passing value is lower, although his shooting is a bit better. Ronaldo may have no credit at all from passing, but his three goals and 11 on-target shots, from distances of 12 to 26 metres, have contributed five times the value that Pirlo and Schweinsteiger got from their attempts.

@Gosia_Bak: Why is Gerard Piqué higher in the Index than Sergio Ramos?

Castrol: The difference between them is very small – Piqué has an overall mark of 9.38 and Ramos 9.25. Perhaps what gives Piqué a small advantage is that he has prevented an opposition pass on 51 occasions compared to 39 from Ramos. In any case, the points' difference between them is not significant.