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Please note: The algorithm descriptions in English have been automatically translated. Errors may have been introduced in this process. For the original descriptions, go to the Dutch version of the Algorithm Register.

Signal model Transfer Tax for returns (OVB)

Dutch Tax and Customs Administration

This is a signal model for the Overdrachtsbelasting (OVB). The model checks whether claims for the OVB start-up exemption or the low OVB rate are justified. The throw-out reasons follow (in)directly from the law. If a return meets one of the throw-out reasons, there is a chance that the claim (exemption/low rate) is not justified. The processing should then reveal what is going on.

Last change on 10th of September 2025, at 14:59 (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

09-2024

Contact information

algoritmeregister@belastingdienst.nl

Link to publication website

https://over-ons.belastingdienst.nl/onderwerpen/omgaan-met-gegevens/algoritmeregister/

Link to source registration

https://over-ons.belastingdienst.nl/onderwerpen/omgaan-met-gegevens/algoritmeregister/signaalmodel-ovb-voor-aangiftes/

Responsible use

Goal and impact

For the Real Estate Transfer Tax (OVB), a special signal model has been developed that supports supervision of the use of the reduced rate and the start-up exemption. The throw-out reasons are (in)directly based on statutory provisions. All returns claiming these favourable schemes are automatically passed through this risk model and registered.

It is an algorithm that identifies discrepancies in the declaration data. It checks whether the declared values match the legal criteria applicable to the reduced rate or the start-up exemption. When discrepancies are found, the algorithm assigns a score for each failure reason. These scores are then displayed cumulatively to handlers of OVB returns. Based on these scores, handlers can take targeted action.

The ultimate goal of the algorithm is therefore to effectively monitor the correct use of tax schemes within the OVB.

Considerations

The algorithm makes it possible to check OVB declarations systematically and thoroughly. This strengthens the quality of supervision and ensures that citizens and businesses get clarity on their returns faster. Without the signals generated by the algorithm, targeted supervision is hardly feasible.

We want to carry out this supervision in a careful and data-driven way. In this respect, the algorithm acts as a support tool for Tax and Customs Administration staff. This allows them to assess returns more accurately, efficiently and uniformly.

Human intervention

Human intervention in the Tax Administration context implies that a competent and knowledgeable employee plays a substantial role in decision-making.

This signalling model always involves human intervention in decision making. The algorithm detects and selects data discrepancies in the return compared to the legislation, in the form of signals. It is the Inland Revenue's OVB employee who makes the decision.

Risk management

The General Administrative Law Act (Awb) prescribes that the government's actions are transparent and lawful. When applying and developing algorithms, the Tax and Customs Administration observes the general principles of good governance.

The Tax and Customs Administration drew up conditions for the development of algorithms, a quality framework. This sets out the rules and agreements followed when developing the algorithm. The conditions of the National Audit Authority are leading in this respect. At set moments, the Tax and Customs Administration checks whether the algorithm still meets the quality requirements.

The algorithm uses data collected for various tax laws. As required by the AVG, no more data is used than necessary.

The selection rules are reviewed periodically and adjusted if necessary to remain compliant with laws and regulations.

Legal basis

  1. General State Tax Act:
  2. Regulation implementing the General Act on State Taxes
  3. General Administrative Law Act:
  4. Taxes on Legal Transactions Act
  5. Implementation Decree on taxation of legal transactions
  6. General Data Protection Regulation
  7. General Data Protection Regulation Implementation Act:
  8. Citizen Service Number (General Provisions) Act:
  9. Archives Act 1995:
  10. Registration Act 1970
  11. Regulation implementing the Registration Act 1970
  12. Notary Act
  13. Electronic Notarial Deeds Registration Act
  14. Regulation on electronic notarial acts
  15. Regulation on electronic notarial acts

Links to legal bases

  • General State Tax Act:: https://wetten.overheid.nl/BWBR0002320/
  • Regulation implementing the General Law on State Taxes: https://wetten.overheid.nl/BWBR0006736/
  • General Administrative Law Act:: https://wetten.overheid.nl/BWBR0005537/
  • Law on taxation of legal transactions: https://wetten.overheid.nl/BWBR0002740/
  • Judicial Traffic Taxes Implementation Decree: https://wetten.overheid.nl/BWBR0002770/
  • General data protection regulation: https://eur-lex.europa.eu/legal-content/NL/TXT/HTML/?uri=CELEX:32016R0679
  • General Data Protection Regulation Implementation Act:: https://wetten.overheid.nl/BWBR0040940/
  • General provisions Citizen Service Number Act:: https://wetten.overheid.nl/BWBR0022428/
  • Archives Act 1995:: https://wetten.overheid.nl/BWBR0007376/
  • Registration Act 1970: https://wetten.overheid.nl/BWBR0002739/
  • Regulation implementing the Registration Act 1970: https://wetten.overheid.nl/BWBR0034017/
  • Notary Act: https://wetten.overheid.nl/BWBR0010388/
  • Electronic Registration of Notarial Deeds Act: https://wetten.overheid.nl/BWBR0032526/
  • Electronic notarial act regulation: https://wetten.overheid.nl/BWBR0047875/
  • Electronic notarial act regulations: https://www.wet-en-regelgeving-notariaat.nl/cms/showpage.aspx?id=26067&folderNr=1036

Elaboration on impact assessments

  • Privacy and AVG

The use of data is tested against the General Data Protection Regulation (AVG). Testing personal data reveals any privacy risks and allows appropriate measures to be taken.

The AVG prescribes that no more data should be used than necessary. This is called data minimisation. The Tax Administration regularly examines whether the data used are still necessary and may therefore be used.


  • Use of special personal data

The algorithm does not use special personal data.


  • Equality and non-discrimination

The selection rules in the algorithm are tested against non-discrimination legislation. Processing as little personal data as possible reduces the risk of direct discrimination. Employees involved in developing and managing the algorithms receive training on data protection and bias.

Operations

Data

  1. Personal data taxpayer
  2. Notary tax return data, transfer tax administration
  3. Property data

Links to data sources

  • Personal data taxpayer: Basisregistratie Personen (BRP)
  • Notaries' data declaration, transfer tax administration: ROB (Teradata)
  • Real estate data: WOZ, Kadaster, BAG

Technical design

The algorithm consists of selection rules created by content experts based on laws and regulations.

The algorithm is not self-learning. This means that the algorithm does not develop itself during its use.

External provider

The algorithm was developed by Tax Administration staff and is also maintained internally.

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