The fact is, I don't know. My point is, neither does anyone else. These studies are merely thin cross sections comparing tires in gross ways under artificial conditions. I have seen nothing that attempts to quantify a physical property to rolling resistance. I haven't seen anything testing the sensitivity of these results to the variables such as rider weight and air pressure. You would think that someone would've at least taken some pictures measuring the tire deformation at the contact patch under different conditions to go with their gross power measurements.

For example, many people here subscribe to the notion that increasing air pressure in your tires past, say, 110psi, on real roads (irregular surfaces), doesn't necessarily decrease rolling resistance. Yet it's pretty easy to see on rollers that increasing the air pressure will always decrease resistance; I believe some of the testing results from Jobst Brandt indicates the same. Who is correct here? Or does it depend on the tire brand, road surface, tire pressure, or all of the above and to what extent? What does that mean when put in terms of Mr. Coggan's testing?

Obviously different tires have different rolling resistance. But until this fact is linked to physical properties of the tires in question, then all the ad hoc testing by all the garage scientists in the world won't aid a racer trying to find the best tire for his needs.