bgh appears to have taken a stats/science class in which he learned that "correlation does not equal causation" and that actual practice is irrational. Well, many people try to negative split the 800m and few succeed unless they are running well below their capacity. For instance, Brazier in high school was running 1:47 or 1:48 races with major negative splits. It was obvious that he could run a lot faster with a faster first lap. In college, he got precisely that situation right off the bat and at NCAA's and he ran 1:45.93 and 1:43.55(?), both positive-split. You have the ATP system going only for the first maybe 6-10 seconds, so that alone is reason to have a fast first 200m without it costing you too much, and then after 200m, you will in elite races have pacers until about 450-600m, more reason to slow down the second lap or the third or fourth 200m, since you don't have anyone to draft off of. Those in 2nd or 3rd place will have drafting if they are close enough--which helps those who go out slower and wait behind the others for them to die, to run more even splits--they get the drafting advantage for the entire race or close to it, just going wide the last 100m usually.