WOZ valuation model

Municipality of Achtkarspelen

xxllnc Appreciate

Last change on 4th of September 2025, at 8:36 (CET) | Publication Standard 1.0

• Publication category: Impactful algorithms
• Impact assessment: Field not filled in.
• Status: In use

General information

Theme

Public finance

Begin date

2018-12

Contact information

[e-mail]

Link to publication website

https://www.achtkarspelen.nl/woz-waarde

Responsible use

Goal and impact

The purpose of the applied algorithms is to calculate the market value of immovable property under the WOZ Act. The level of the WOZ value has several implications for stakeholders (citizens and businesses). The main impact is in direct taxes, such as property tax and advertising tax. In addition, the level of the WOZ value -directly or indirectly- affects other taxes, such as inheritance and gift tax, income tax and corporation tax

Considerations

For the efficient, correct and uniform calculation of the WOZ value, the use of valuation models is crucial. Without these models, this is not possible.

Human intervention

The WOZ value is formally determined - under Section 22 of the WOZ Act - by the levy officer. To arrive at a value determination, ex. Section 17 of the WOZ Act, the value is determined. Determining the WOZ value is de facto done by the WOZ assessor, who makes use of assessment models as much as possible. These models consist of a series of algorithms.

Risk management

Risk in use is limited because the Valuation Chamber oversees the implementation of the WOZ.

Legal basis

Property Valuation Act (WOZ)

Links to legal bases

Property Valuation Act:: https://wetten.overheid.nl/BWBR0007119/

Operations

Data

Basis when determining residential properties are the realised sales figures from the land register.

Basis for non-residential properties are in principle rental figures.

Technical design

Xxllnc Valuation uses model-based comparison. Model-based comparison means that in substantiating a property, sold properties are sought which are most similar to the main building of the property being compared. The following principles apply:

• The value of the main building is determined by comparing it with the main building of reference points;
• The value of the land and other components are determined by using model key figures;
• Valuers set the parameters of the model, such as utilisation area, year of construction, location, quality, maintenance, etc.

External provider

XXLLNC