Arizona Cardinals vs San Francisco 49ers — Win Probability

49ers' 6-point win falls short of model's 7.6-point projection

San Francisco's 36-30 victory over Arizona in Week 3 played out closer than the pregame model expected, though the outcome itself aligned with consensus.

The model projected the 49ers to win by 7.6 points with a 72% win probability, slightly more confident than the market's 7.5-point spread suggested. Both assessments favored San Francisco decisively—this was not a coin flip, and the outcome confirmed that read.

What actually happened was a one-point tighter result. The 49ers won by 6 instead of 7.6, a gap of 1.6 points. The model's expected scoring was 28.1 for San Francisco and 20.5 for Arizona. The actual final was 36-30, meaning the 49ers outscored the projection by 7.9 points while Arizona exceeded its projection by 9.5 points. Both offenses performed above the model's preseason expectation.

This was not an upset—San Francisco was favored and won. The model's directional call was correct. The magnitude of the miss, however, was modest. In a game where the projection called for a touchdown margin, the actual result came within a field goal of that expectation. For a single-game forecast in the NFL, where variance is high and scoring ranges are wide, this represents a close read rather than a significant miss.

The 49ers improved to 3-0. Arizona fell to 1-2. The model correctly identified San Francisco as the superior team and the likely winner. It slightly overestimated the margin because both teams scored more than anticipated, which compressed the outcome without changing which team won. In predictive terms, this was a qualified success—the forecast nailed the winner and was only slightly off on the spread.