Sales ratio study

A sales ratio study compares what assessors said properties were worth against what those properties actually sold for.

Minnesota's Department of Revenue publishes them annually, by county and by property class, and they are the mechanism by which the state checks that assessment is tracking the market.

The ratio#

For each qualifying sale: the assessor's estimated market value divided by the actual sale price.

A ratio of 0.95 means the assessment was 95 percent of the sale price. Above 1.0 means the assessment exceeded it.

Aggregated across a county and a property class, the distribution of those ratios describes how well assessment is performing — both its central tendency and its consistency.

Where the data comes from#

The eCRV — the electronic Certificate of Real Estate Value filed when Minnesota property changes hands for more than $3,000.

That connection is worth drawing out. An eCRV is a form completed at closing that feels administrative. It is also the input to the study that governs assessment across the entire county.

A misreported price — personal property not itemised and deducted, consideration stated incorrectly — distorts the ratio and therefore the assessment of every neighbouring property that the study influences.

What the state does with it#

Sales ratio studies inform equalisation: where assessments in a jurisdiction are systematically out of line, the state can act to bring them into range.

They also feed the calculation of aid formulas and other distributions that depend on property values being comparable across jurisdictions.

What it means for a property owner#

Context, not evidence.

A study showing assessments in your county running above sale prices supports an argument that the general level is high. It does not establish that your particular property is over-assessed, and a board or court will want evidence specific to your property.

Comparable sales, an appraisal and documented condition problems carry an individual appeal. The ratio study is the backdrop.

Why it matters for valuation work generally#

It is one of the few published, independent measures of how accurate property assessment actually is — computed on real transactions, by county and class, every year.

For anyone building a valuation model on Minnesota data, it is the benchmark that already exists. Any model claiming accuracy should be able to state how it performs against the same measure the state applies to assessors, on the same data.

Why the studies are worth reading anyway#

Even where they cannot carry an individual appeal.

They tell you how well assessment is performing in a specific county and a specific property class, which is context nobody else publishes.

A county whose residential ratios are consistently tight is assessing carefully. One with wide dispersion is producing values that are right on average and wrong on many individual properties — which means the chance that any particular assessment is out of line is considerably higher, and an appeal correspondingly more likely to succeed.

For anyone deciding whether an appeal is worth the effort, that dispersion figure is the most useful single number available, and it is free.