Just a number of fundamental flaws with the analysis ...
First, having been the person directly involved with the Letter Writing Campaign, I can tell you nearly 1/3 of all registered voters in Iowa are "no party". Over 700,000 people.
Second, taking the 6% figure and extrapolating it to an entire set of registered voters is an incorrect assumption. You have to realize there are many people who might be Ron Paul supporters, but have never even heard of the guy! Your analysis assumes 100% recognition, which is impossible. Hell, a poll came out today that shows 12% of Americans think Rudy Giuliani is still mayor of NYC!
Third, saying only 17% of Ron Paul supporters went to the caucus is just untrue. Directly tied with the second point above.
To me, the analysis basically says, "if we made more people aware of Ron Paul, more people would vote for him". Uh, yeah ... don't think anyone is denying that.