Readers should note that the list is created mid year, so it takes the previous season and the beginning of the latest one into consideration. When this one was done, Sebastian was double champion, but his prospects for 2012 looked slimmer than in previous years, due to the less than stellar performance of the Red Bull at that point - hence a small drop. Lewis had come off of a comparatively poor performance in 2011 (as compared to years before), but things were looking up for him in 2012; hence a drop, but not too steep. Sebastian obtained the Ambassadorial role for Infiniti - personal sponsorship, so that would be taken into account, as would any other sponsorship these two drivers obtained.
Many other factors are taken into consideration as motivators for increased sponsorship interest and overall marketability. For example, if it is an olympic year, you will see more olympians. If there are other major sporting events on the horizon, those competing (and thus hot marketing prospects) will be included. General factors like character likability, continued success over a period of time, the visibility and pervasiveness of the sport, and many other factors impacting marketability are also taken into account.
How accurate are they? Who knows - but one thing is certain, the entire top 20 are incredibly marketable in the years cited, lol. There may be other F1 stars among the 50 - I didn't look through the entire list, so feel free to point them out if you come across them.
Edited by bourbon, 26 January 2013 - 19:34.