I understand that looking at just the number of years in the research isn't as telling as looking at the differences in the numbers of dogs included in the research, but it appears Interceptor was studied over 9 yrs, Sentinal over 5 yrs, and it doesn't say the number of years for Revolution (weird!?) My "guess" would be that a product that has been used over a long period of time would more than likely have more "participants" than a product that has been around for a shorter period of time. Of course, unless we saw the actual numbers, we'd never know....just be guessing. The article mentions a 2004 FDA source, so it may be possible to get the actual results of the research....probably have to do some digging though!
