Week 1 of the 2026 NFL season is done. Sixteen teams are 1-0, sixteen are 0-1, and every sports show is already telling you who is "for real." I build a Monte Carlo simulator that estimates NFL playoff odds for all 32 teams, so I wanted to know how much one week should move those numbers. The model's answer is "not much," and the reasons are more interesting than the numbers themselves. The problem with one game of data A common way to estimate team strength is the Pythagorean...