We're four races into a probably 19 race season (there's still a chance the inaugural Russian Grand Prix, due in October, could be suspended or cancelled for political reasons). Intriguingly, every single qualifying session and race, excluding Australia where Hamilton suffered a DNF due to reliability failure, has been identical to 2013 in terms of which Mercedes driver was faster.
Now, that could be coincide but it's 7/7 which suggests that even if last year isn't a perfect guide, it's at least worth bearing in mind. However, there were a few DNFs last year. In addition, the Indian Grand Prix has gone (huzzah), we see the return after some time of the Austrian A1 Ring, and the probable first race in Russia. Upon checking, we also lost Korea.
So, even though we have 15 races still ahead, not all of them can be considered for predictive purposes. Here's how they stacked up in 2013 (first name is qualifying 'winner', second the highest placed in the race):
Spain – Rosberg Rosberg
Monaco – Rosberg Rosberg
Canada – Hamilton Hamilton
Great Britain – Hamilton Rosberg*
Germany – Hamilton Hamilton
Belgium – Hamilton Hamilton
Italy – Rosberg Rosberg
Singapore – Rosberg Rosberg
Abu Dhabi** - Rosberg Rosberg
USA – Hamilton Hamilton
Brazil – Rosberg Rosberg
*Hamilton suffered a tyre explosion, the race result could easily have been different
** double points this year, of course. Bloody stupid rule, but one we must consider.
So that gives:
Rosberg: Spain, Monaco, UK*, Italy, Singapore, Abu Dhabi, Brazil
Hamilton – Canada, Germany, Belgium, USA
That's 8 (counting Abu Dhabi double) for Rosberg to 4 for Hamilton. If Mercedes maintain their dominance and all else is equal (ie neither driver is more disadvantaged by misfortune than the other) then that would give Rosberg a lead of 28 points (4 x 7, the advantage a winner has over second place).
However, the Silverstone race was bad luck on Hamilton's part. If we shift it to Hamilton's column, we get 7:5, a Rosberg advantage of 14 points.
There are also other races we need to consider, namely: Hungary, Russia, Austria.
I've glanced at the circuits, and would guess Rosberg might do better as Austria and Hamilton Russia. Not sure about Hungary. Very hard to pass there, so it could well come down to the start.
Now, if the above is vaguely accurate, the title race will be on a knife-edge. Happily, we'll get a pretty quick indication whether or not the 7/7 is a coincidence, or whether it really does point the way of things to come. Rosberg has to win either Spain or Monaco (or both) to keep his hopes alive. If he does, then I would make him marginal favourite.
Hamilton is driving extremely well, and he's rightly considered favourite for the title. But if the pattern persists, it'll be very close and will go down to Abu Dhabi.
However, as well as the relative performance of each driver we need to consider whether or not Mercedes will maintain, lose or even increase their advantage over the rest of the field. A large part of it comes from having the best engine and having configured it in a way which is (if you are an engineer and understand this sort of thing, which I'm not and don't) fantastic. Improved software will see Ferrari and Renault engines improve, but they won't match Mercedes.
Aerodynamically Red Bull remain top dog, but Mercedes aren't too far behind and are probably ahead of everyone other than Red Bull.
It's possible Red Bull, Ferrari, Force India and McLaren might nab the higher spots now and then. Pushing a Mercedes driver down to third would cost him an extra 3 points to his team mate (assuming the other wins), and down to fourth would cost 3 more on top of that.
But, if other teams won (followed by Mercedes 2-3) that would push them down to getting 18 and 15 points, decreasing the advantage the lead driver would get.
We might well have the title decided by reliability of the car and consistency. Spain and Monaco will be useful. If Rosberg loses both, it's pretty much goodnight Vienna. If he wins one the game is afoot (especially if it's Monaco). If he wins both then it's advantage Rosberg.