Algorithm Support Office Handling

Dutch Tax and Customs Administration

The 'Support Office Handling' algorithm helps Inland Revenue employees respond to discrepancies found in the wage return. The algorithm puts certain wage declarations in the throw-out or drop-out. It helps employees review and test the ejected wage returns.

Last change on 22nd of April 2025, at 15:18 (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

Field not filled in.

Contact information

[e-mail]

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/ondersteuning-kantoor-afhandeling/

Responsible use

Goal and impact

The Tax Authority checks withholding agents for correct and complete declaration and payment of payroll taxes. Payroll taxes consist of wage tax, national insurance contributions, employee insurance and the income-related Healthcare Insurance Act contribution. Withholding agents (such as an employer, pension fund or benefits agency) deduct the wage tax and national insurance contributions from their employee's pay and, in some cases, the income-related healthcare insurance contribution. They remit this to the tax authorities. The employee insurance contributions and usually the income-dependent healthcare insurance contribution are not deducted from the employee's salary, but are paid by the employer to the Tax Administration.

A withholding agent must periodically send a payroll tax return digitally to the Tax and Customs Administration. In the Inland Revenue's process, the messages of these wage returns are accepted and processed in a mass automated manner.

After receiving the wage return messages, the system performs checks. A wage declaration that cannot be processed in the mass approval process enters the process as an ejection. A wage declaration in which errors, such as an unknown LH number or an incorrect time period, have been identified, enters the process as throw-out. A treatment of throw-out may result in rejection of the submitted wage return. A handling of throw-out can lead to a levy decision in the form of an after-tax assessment, reduction or refund. The purpose of this process is to ensure proper administrative processing and assessment of amounts in the wage returns.

Based on the clues from the algorithm, the handler can assess the throw-out or drop-out of the wage return notices. It is the Inland Revenue handler who ultimately determines whether the wage return contains inaccuracies and can contact the withholding agent.

Considerations

Assessing throw-out and drop-out in payroll returns is important for the withholding agent to achieve correct administrative processing and assessment of amounts in payroll returns. The algorithm can support an employee of the Tax Administration in this process. As a result, the assessment is more careful, efficient and uniform.

Human intervention

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

The operation of the algorithm always involves human intervention. The algorithm detects and selects. It is the Tax Administration employee who makes the decision whether to contact the withholding agent.

Risk management

The General Administrative Law Act (Awb) requires the government's actions to be transparent and lawful. The Tax Administration observes the general principles of good governance when applying and developing algorithms.

The algorithm uses data collected under 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. General Administrative Law Act:
3. General Data Protection Regulation:
4. General Data Protection Regulation Implementation Act:
5. Payroll Tax Act 1964:
6. Social Insurance (Funding) Act:
7. General provisions Citizen Service Number Act:
8. Archives Act 1995:
9. Unemployment Act:
10. Sickness Act:
11. Work and Income according to Labour Capacity Act:
12. Disability Insurance Act:
13. Health Insurance Act:

Links to legal bases

• Algemene wet inzake rijksbelastingen: : https://wetten.overheid.nl/BWBR0002320/
• Algemene wet bestuursrecht: : https://wetten.overheid.nl/BWBR0005537/
• Algemene verordening gegevensbescherming: : https://eur-lex.europa.eu/legal-content/NL/TXT/HTML/?uri=CELEX:32016R0679
• Uitvoeringswet algemene verordening gegevensbescherming: : https://wetten.overheid.nl/BWBR0040940/
• Wet op de loonbelasting 1964:: https://wetten.overheid.nl/BWBR0002471/
• Wet financiering sociale verzekeringen:: https://wetten.overheid.nl/BWBR0017745/
• Wet algemene bepalingen Burgerservicenummer:: https://wetten.overheid.nl/BWBR0022428/
• Archiefwet 1995: : https://wetten.overheid.nl/BWBR0007376/
• Werkloosheidswet:: https://wetten.overheid.nl/BWBR0004045/
• Ziektewet:: https://wetten.overheid.nl/BWBR0001888/
• Wet werk en inkomen naar arbeidsvermogen:: https://wetten.overheid.nl/BWBR0019057/
• Wet op de arbeidsongeschiktheids verzekering:: https://wetten.overheid.nl/BWBR0002524/
• Zorgverzekeringswet:: https://wetten.overheid.nl/BWBR0018450/

Elaboration on impact assessments

• Privacy and AVG

The use of data is tested against the General Data Protection Regulation (AVG). Reviewing 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 Support Office Handling algorithm does not use special personal data.

• Equality and non-discrimination

The selection rules in the algorithm are checked 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

• Identifying data (including LH number)
• Payroll tax details
• Payroll tax return details

Links to data sources

• Identificerende gegevens (o.a. LH-nummer): Belastingdienst
• Relatiegegevens Loonheffingen: Belastingdienst
• Aangiftegegevens Loonheffingen: Belastingdienst

Technical design

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

The algorithm is not self-learning. That means it does not evolve as it is used.

External provider

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