The way Brett Larner sets up his argument is bogus. He makes too many assumptions and pretends to produce an objective, number-based argument with pretty Excel tables. More importantly, he does not address all of the confounding variables which might make a simple comparison of 5k times not so simple. For example, here are a few reasons why simply comparing the 5k times is not credible: weather (what was the dewpoint temperature at each race location? - which is spatially comparable by the way unlike humidity percentages), elevation (self-explanatory), type of race (i.e. an invitational-type race tends to be fast and conducive to prs while championship races are not run all out but rather erratically in order to win...in this case it would be unfair to compare say Galen Rupp's winning time at the Olympic Trials - 27...something to a Japanese runner's pb at an invitational-type race). The only way to compare Japanese Runner times to American ones and control for all of these variables would be to have them run in the same race. Geesh what a concept.
And, in general, why does he have to present the article like that anyway? The argument in his blog is subtly pitting the US runners against Japanese ones to prove...what, exactly? I think it would have been better to report their times and show how good they are doing and talk more about their focus on longer distances. You see, that sort of cultural analysis is interesting. But the way he presents it may potentially get people riled up unnecessarily.