OfferBackedBuyer Tools

How the OfferBacked heat score works

A plain-English look at the numbers behind our market pages: what we measure, how we combine it, where the data comes from and how often it changes.

The short version

The heat score ranks how competitive each ZIP code is compared with the other ZIP codes we track, on a scale of 0 to 100. It combines four measures of competition from recent home sales. It describes what already happened; it doesn’t predict prices or tell you when to buy.

The four inputs

MeasureWeightDirectionWhat it means
Share sold above original list35%Higher is hotterThe share of homes that sold for more than the price they were first listed at. Using the original list price means a home that was cut and then sold near its reduced price doesn’t count as a bidding war.
Average sale-to-list ratio25%Higher is hotterSale price divided by list price, averaged across sales. 103% means homes sold for 3% over list on average.
Months of supply20%Lower is hotterHow long it would take to sell every home currently for sale at the recent pace of sales, if no new homes were listed.
Median days on market20%Lower is hotterHow long the typical home was listed before going under contract.

How the score is calculated

  1. For each ZIP code, we take the four measures for the latest 3-month period.
  2. For each measure, we find where the ZIP code falls among all the ZIP codes we track for that same period, as a percentile from 0 to 100. For months of supply and days on market, lower values count as hotter.
  3. We combine the four percentiles using the weights above. The result is the heat score.
  4. We rank each ZIP code within its own area and across all the markets we track.

We calculate it two ways. The heat score compares ZIP codes within our featured areas, where we publish monthly rankings; every featured area is a large, competitive metro, so a heat score of 50 means typical for those markets. The competition score on every ZIP code’s page uses the same four measures and weights but compares against all U.S. ZIP codes with enough sales, so 50 means typical for the country.

When a ZIP code isn’t ranked

A ZIP code needs at least 15 home sales in the 3-month period to get a score. With fewer sales, one or two unusual deals can swing the numbers too much to compare fairly. ZIP codes with missing or implausible values are also left out that month. Their market pages still show the underlying numbers, marked as not ranked.

Seller’s, balanced and buyer’s markets

Separately from the heat score, each market page shows a label based on months of supply, the standard measure most agents use: under 4 months is a seller’s market, 4 to 6 months is balanced, and more than 6 months is a buyer’s market.

Where the data comes from

Redfin revises recent figures as late sales records arrive, so the latest month can change slightly. We re-import the data on a schedule and update scores when it changes.

Coverage

Market pages, the competition score and our ZIP-level tools cover every U.S. ZIP code for which Redfin publishes recent sales figures. Metro-level figures (price cuts, cancellations, buyers vs. sellers, financing and the home price index) cover the metro areas Redfin reports; each ZIP code is matched to its metro area through its county. Property taxes, loan limits, closing-cost rules and down payment programs cover all 50 states and the District of Columbia.

Featured areas

We publish monthly rankings, area reports and the Bidding War Index for these areas:

Latest period: 531 of 689 ZIP codes had enough sales to be ranked.

Quality checks

Before any new data reaches the site, we check that it downloaded completely, that it’s recent, that every featured area is present, that the nationwide ZIP count hasn’t dropped sharply, and that no ZIP code jumped by an implausible amount from one period to the next. If anything looks wrong, nothing is published until a person reviews it.

What the heat score is not

Questions or a correction? Contact us.