I used the SAME method, SAME calipers, and SAME person taking the measurements (myself), the entire time. The results were as accurate as they could possibly be.
Maybe you have missed every single post of written on the topic of body composition, but the key to charting progress with body composition tools is to use a method that is convenient and reliable. Skinfolds and bioelectrical impedance can meet both of these needs when used correctly.
Not all of us have access to multi-compartment models of body composition. Even if we did, it would be impractical if everytime you wanted to measure your body comp, you had to come to the lab fasted, give blood, urine, or respiratory water sample and drink some D2O, hop on the DXA, get tossed in the hydrostatic weighing tank and then give some more blood, urine or respiratory water. Some people may get lucky and participate in a study where the researchers measure their body comp via a 4-compartment model, but most don't get that oppurtunity. They have to use what is available to them.
Accuracy is secondary when it comes to tracking body composition anyway. Reliability and convenience is king. Skinfold measurement, bioelectrical impedance, athropometrics and pictures are really the only tools that most T-mag readers have access to. While DXA has some advantages, it would be cost prohibitive for most T-mag readers. It is a technique that I really like and provides great info including regional body comp and bone mineral content and density, but it is also a technique that is also wrought with problems.
So what are people supposed to do if accuracy is such an important consideration? Should they lift with exactly calibrated weights and dumbells? Should they not pay attention to the calorie readouts on the treadmill because they did not measure VO2?....Obviously not! The big plates may not be perfect 45lbs, but they should at least be in the ballpark. The calorie readouts may not be perfect, but if I enter my weight each time, can't I at least use the calorie readout to calculate work density?
I hope you see my point. We need tools to help us track our progress! Honestly, I understand where you are coming from, but my ideas have come from reading countless journal articles, textbook chapters, and books; not to mention countless conversation with professors, exercise physiologists, doctors, T-mag readers, T-mag contributors and other health professionals. If all goes well, you will get a chance to read my thoughts this Friday. Please take a look and let me know your opinion. I have great respect for your opinion and your contribution to T-mag and the iron game in general, but it was a low blow to attack my friend like that. You will see his response to you is exactly the type of body composition advice that I'm giving to the general T-mag audience.
Like I said, I'd love to hear your thoughts after you get a chance to read the article.
Thanks,
Jason Norcross