September 29, 2026 Public Market Research Methodology
Own It Northwest reviewed public Portland city, Multnomah County, Oregon and national observations from Zillow, Redfin and Realtor.com. Each observation retains the provider's label, geography, period, population definition and source URL.
Acquisition and verification
Source pages were retrieved on September 29, 2026. Values were transcribed from visible provider pages and checked against the provider's methodology or data dictionary where available. No paid provider, private MLS feed or client MLS export was used in these four reports.
Calculations
Dollar differences use direct subtraction of the displayed figures. Percent differences divide the dollar difference by the named comparison figure. Calculations use displayed values without invented hidden precision. Results are rounded to one or two decimal places.
Missing values and sample sizes
The cited city pages did not publish the record-level sample sizes underlying the displayed metrics. These are labeled Not supplied, not zero. The article metadata counts documented metric observations, not properties.
Geography and comparability
Portland city, Multnomah County, Oregon, the United States and the Portland metro are different populations. Modeled values, listing medians, sale medians, rent indices and listing-rent medians are not merged into a synthetic market price. Historical values can be revised by the providers.
Excluded claims
The reports do not estimate an individual property's value, infer a neighborhood or luxury segment, calculate appreciation from unlike measures, identify seller motivation, forecast prices, or establish rent-versus-buy superiority. No current public RMLS report was verified from the association in this review, so current RMLS figures were excluded.