Walden Race Rule #3: Win it at the line!
The Science:
1) As the level of competition increases - from local to state to national to international, the differences in abilities between riders becomes more compressed, and winning by a huge margin in the sprint becomes less of an option. This is where strategy and skill replace the minute differences in ability. By mastering the 'surge to the line' technique using the draft to its maximal effectiveness, a racer with less endurance or with less sprint horsepower can make up for those weaknesses, and maximize their strengths using this technique.
2) Gauging the distance to the line, the movements within the pack, and knowing which wheel to follow - this is the science of this rule.
The Art:
1) Learn to read the race patterns - and know exactly where to be in the pack to avoid the to antithesis to "finish at the line" which are a) being hung out to dry - out front to early fighting the wind or b) getting caught in the back - no place to go, energy available with no outlet
2) Intuitively understand how corners, wind, gradient (uphill/downhill), heat, and race speed combine with the twitching mass of riders in the pack to create final sprint conditions. In one race it might be a single file leadout string where being in 3rd place with a lap to go is the winning strategy. In another, being 20th and following the pending surges might be the right position.
3) The best way to predict a sprint finish other than real time intuition, is to participate in prime sprints. I usually surf the prime sprints (I rarely contest them) in order to gain more information around how the sprint will play out. No guarantee that if the prime sprint surged on the right that the final sprint will as well, but odds are probably 60/40...
This race rule is much more art than science ultimately requires experience to develop. Back when I was racing on the 7-11 team, my teammates used to try to set up leadouts for the sprint finish and I found time and again that I could read the race better than I could utilize their leadouts and I usually abandoned the leadouts (much to their chagrin).