I've spent many hours on FM15, using various editors, to try and find out more about some of the things brought up in this thread. My timing is dreadful but this might help genie in further refining his excellent formulas for position ratings. Here is what I found:
Fascinatingly, CA (current ability) isn't actually based on all the attributes added up. It's based on an algorithm that gives strongest weighting to all the "key attributes" for a role. It is discussed in this thread -
http://community.sigames.com/showthread.php/381779-Current-ability-cost-of-of-attributes-position-breakdown. There are some attributes that have been given bizarrely high or low weighting for the players position, like heading for goalies. The ability to use the weak foot well is crucial in almost all positions. I think this more accurately reflects what SI think the attributes mean, which has always been loosely described.
The main problem with CA is that if a player has more then one natural position, like a DC/DM, the CA is split between the two positions. While Positional rating is based purely on how good that player is in one position, which is better for precise scouting.
I decided to create my own positional rating for genie scout, based on the algorithms used for CA. I used the methods from the quoted thread to work out the weighting cost for each attribute in FM15. I then compared my positional rating with Genies. Again, the findings were interesting...
My ratings closely matched CA, when a player is only natural in one position. For instance, Godin and John Terry have similar CA. Both are natural CB, who can't play in other positions. Yet, genie's positional rating has Terry at 82.41% and Godin 77.21%. When I change to my positional rating they have positional ratings of 72.4 and 72.78. Which is much closer. Another example is Garay and Carvalho. Again, both are only natural in one position. Garay has a much higher CA of 152 to Carvalho's 140. Yet, genie's positional rating has Carvalho higher with 74.6 and Garay at 70.96. When I changed to my positional ratings, it was again in line with CA - Garay had 70.04 and Carvalho 66.84.
I also noticed that if you hire top scouts and coaches, the players in your squad that they recommend in the squad depth report, tend to be the players with the highest CA, or my positional rating. The scout were less reliable. Even a top scout, with high Judging CA, was recommending good players above other players who were excellent for CA, or my positional rating.
Whether the key attributes weighted for the CA, or the positional ratings that Genie's has carefully refined based on real life footie, have more influence on player performance is a big question. I might send a tweet to Miles Jacobson, or someone at SI, to see how important the weighted attributes are for CA to how a player performs in match. Although, I don'd see why these attributes would be put as "key attributes", or weighted this way if they didn't impact the match engine.
Also, FM doesn't have a CA weighting for Target men, only one rating for CF. So I did the Target Man position rating based on role rating. This didn't work at all. I found that most attacking players had target man as the best positional rating. Even players like Luis Suarez! If you sorted Genie Scout by best positional rating, the list was dominated by Target Men. I think if you have an advanced tactic and know exactly what you want from a player, it may be best to pick by role rating, included in the G edition. To allay this issue with target men, i set the weighting of Target Men to 0 on genie scout and If I want a target man, I'll bump it back up to 100, or just search by role rating in the G edition.
Hope this doesn't come across as criticism, Genie. I think your scout tool is amazing. I wouldn't find the time to play FM without it and appreciate the long hours that must go into programming the scout each year. I was just sharing my findings. I'm not sure whether to use my positional rating or yours, which is based on real footie and has been refined over many versions.
I can share my positional rating file for Genie Scout, or the document with a list of the attribute coefficients, if anyone is interested in having a tinker.