Methodology

This page explains how HuisWeter turns separate public figures into a report, and where its limits lie. The source and method of each individual figure are shown with that figure; where the data comes from is on the Sources page.

One national scale

A single figure says little: is € 368 a month a lot? So we put every figure on a common national scale. We compare it with a real reference group, for example all neighbourhoods in the Netherlands, and show where it falls. A percentile of 80 means that 80% of the group has a lower figure.

Where a recognised standard exists, such as the WHO guidelines for noise and air quality, we use that standard's own limits instead of a percentile. Where no honest reference exists, we show the figure without a ranking and say so.

Two things that are easily mixed up: the band (low, average, high) always describes the figure itself, even when high is bad. The score is converted so that higher is always better for the buyer.

Themes

The report is built from themes: House, Price & value, Costs, Residents, Crime, Health, Amenities & schools and Environment. A theme with a score combines several figures into one theme score.

Two themes have no score. Price & value puts the WOZ value, the estimated market value and, for a home that is for sale, the asking price side by side. Health describes the neighbourhood's residents, not the home, and only compares its figures with the municipality and the Netherlands. A few figures in other themes do not count towards the score either, because what they describe is not a matter of better or worse, such as population density.

The overall score

The overall score is the mean of the theme scores on a scale from 0 to 100. It is not a percentile and not a grade for the home itself: a 60 does not mean the home is better than 60% of homes. Look at the themes above all, because what weighs heavily is for you to decide.

Missing data

When a figure is missing, we fill nothing in. The figure drops out and the other figures in the theme weigh more. If too much is missing, we report the theme as unavailable rather than show a score resting on a few loose figures.

CBS sometimes withholds figures, for example for very small counts. Such a figure is withheld, not zero, and we never show it as zero. CBS also rounds counts to multiples of five, so the parts of a breakdown do not always add up to the total. We therefore calculate shares over the sum of the parts.

Estimates carry their method

What we calculate instead of measure is marked as an estimate and has a method you can open.

• Market value. Based on the WOZ value, a municipality factor from CBS sales figures, price developments since the valuation date and a correction for how the home differs from its neighbourhood. The result is a range with an 80% chance: 1 in 5 homes falls outside it. It is a statistical estimate, not a valuation.
• Monthly costs. A sum of OZB, sewerage charge, waste charge, water board charges, energy, a maintenance reserve and buildings insurance. The charges follow the rates of the municipality and the water board; the energy costs follow the average use of this kind of home in the municipality (CBS), not the use of the current occupants. A mortgage is not included. The monthly costs are compared with the rest of the Netherlands, so a large, expensive home scores worse here than a small flat.
• Distances. Measured in a straight line from the address itself, not along a walking route. For the ranking we convert them into an estimated road distance so that they compare with the CBS figures.
• Schools. Results are compared only with schools in the same group (the same test or school type), because the tests do not score on the same scale.
• Health and living environment. The Health Monitor figures are RIVM model estimates for the adults in a neighbourhood, not a count. Where RIVM has no estimate for a neighbourhood, we show the district's, without a ranking.

Reference dates

Each source has its own reference date, and years differ even within one source: in an edition of the CBS neighbourhood figures, the number of residents is often more recent than, for example, income. Where it matters, the year is shown with the figure. We only compare figures that describe the same moment, or we say that they do not. The Sources page shows how fresh each source is.

Areas, not people

Neighbourhood figures describe a neighbourhood or municipality. They say nothing about a street, a household or a person, and they are worded factually and comparatively.

Mistakes and improvements

Spotted something that is wrong? Let us know through the Contact page, with the address and the figure.