The Forecast Accuracy Ledger

Every month, when actual home prices publish, we grade the previous month's forecasts against them: ours, and Zillow's published forecast, metro by metro. Wins, losses, and the size of every miss go here. A forecaster who won't show you the scoreboard is asking for faith.

First grading: on or about July 16, 2026. Zillow publishes June's actual home values in mid-July. The June forecasts being graded were locked and archived on July 12, 2026: Sialim's next-month, quarter, and 12-month calls for 894 metros, and Zillow's published forecast from the same date. Neither can be revised. This page states the commitment before the first result exists, so the scoreboard starts honest.

What will be graded

For each of 894 metros: the forecast value against the realized value, the percentage miss, and which engine came closer. The running scoreboard accumulates monthly. Quarter-ahead and year-ahead calls get graded as their target months arrive, so the ledger deepens over time: the June 2026 twelve-month calls get their verdict in July 2027.

Method notes: horizons are aligned to the nearest published month; both engines are graded against the same realized values from the same source. Details on the methodology page. The current standing disagreements are on the Sialim vs. Zillow page.