How we decide, and how you can check us

Everything on this page describes rules we apply in code, the same way for every property. Our recommendations are produced with automated tools. You can ask a person to review any recommendation, and we'll explain the main factors behind it.

1. Which homes count as "similar"

We compare your home with a cohort: a group of similar properties assessed in the same roll.

Similar homes means: same community, same structure type, built within 10 years of yours, living area within ±15%, lot size within ±25%, and at least 8 of them.

If fewer than 8 homes match, we widen the criteria one step at a time and show you which step we used. Wider steps allow more difference in age and size and, as a last resort, reach to nearby streets outside your community. Your result shows the step, so you can judge how close the comparison is.

A few details matter:

• Where a fact is missing, we don't guess it. Calgary's open data doesn't include living area, so for Calgary houses the first comparison uses value per square foot of lot, and we confirm living area from your notice before building a case.
• New Ontario homes are compared with their own subdivision. For new Ontario homes, we compare with homes in the same subdivision built within 2 years of yours.
• The same comparables you see are the ones we use. Your result lists the most similar homes with their public assessed values.

2. What we measure

We compare your assessed value per square foot (of living area, or of lot where living area isn't available) with the median of your cohort. The median is the middle value, so one unusual house doesn't skew it. We also check for record errors: facts on file that don't match your home, such as floor area, year built, basement finish, garage or lot size.

3. What "fairly assessed" means

"Fairly assessed" means we don't think a review would be worth it for you. That can be for one of three reasons, and your result says which:

1. Your value is in line with similar homes. The gap between your value and the cohort median is below our threshold.
2. The saving wouldn't cover the cost. There's a gap, but after our fee the expected result isn't worth your time.
3. A review could backfire. If a review could plausibly raise your assessment, we tell you and don't recommend filing.

"Fairly assessed" is not a judgement about your home or a statement about the law. It's our honest read of the numbers.

4. Why we publish the share told "fairly assessed"

Publishing only wins would be easy. We also publish how often we say "don't bother", because that's how you can tell our recommendations are honest.

Share of completed checks told "fairly assessed", computed live: published once enough checks are complete, out of 6 completed checks.

The number is calculated from every completed check that reached a verdict. Checks still waiting for a notice are left out. We don't show it until there are enough checks for it to mean something.

A high share could also mean we set our bar too high and left money on the table. So we guard against that in two ways:

• We publish the threshold we use to decide "fairly assessed", and every change to it, next to the statistic.

• Each season we offer to file a small, random sample of borderline cases at our own cost, with the owner's consent, to test whether our "fairly assessed" calls were right. The results tell us whether our bar is in the right place. The owners involved are told exactly why they were asked.

5. How the recommendation is made

Today our recommendations come from fixed, published rules and tables, not from a trained prediction model. If that changes, this page will say so before the change takes effect. The tools compute every number. People approve the rules, the thresholds and the wording we use.

6. Where the data comes from

• Alberta: Calgary and Edmonton publish their assessment rolls as open data, and BC Assessment shows each property's assessed value publicly.
• BC: single public lookups of assessed values, used at a respectful pace.
• Ontario: your notice, or MPAC data you authorize us to see.
• Always: anything you tell us or upload, which we treat as yours.

We don't scrape real-estate listing sites or any source whose terms don't allow it.

7. Limits we want you to know about

Public data has errors, and some characteristics aren't published at all. A cohort built from wider steps is a looser comparison. The assessor may know things about your home that we don't. That's why every "you likely have a case" is reviewed against your actual notice before anything is filed, and why you can always ask a person to look at your result.