Let us not forget that Makau (marginally) beat G Mutai (at least) twice: once in Berlin 2010 and once in Rotterdam 2010. A year later, Makau breaks the world record by running 90 seconds faster than previous year.
Logically, we can conclude the following:
1) Makau and G Mutai were in similar shape in 2010
2) Makau is a better racer
3) Makau ran 90 secs faster and G Mutai ran 2 minutes faster in 2011
Does this mean that the wind at Boston 2:03:02 is only worth 30 seconds or so? Or did G Mutai have a bigger improvement?