Dutch Tax and Customs Administration

The Tax and Customs Administration uses a lot of data from citizens and businesses in its services. Computers and algorithms enable us to do our work better, smarter and faster. After all, we cannot think up and process everything manually every time. On this page, we would like to explain what algorithms are, why we use them and what for.

What is an algorithm?

An algorithm is a series of pre-arranged rules and steps that a computer follows automatically. This allows the algorithm to make calculations to solve a problem or answer a question. You can compare an algorithm to a recipe. The data (dates) are the ingredients of the algorithm.

Why do we use algorithms?

The Tax Authority levies, checks and collects national taxes and contributions for all residents in the Netherlands. This is an extensive task. Every citizen must be able to trust that the Tax and Customs Administration performs these tasks carefully and efficiently. For income tax alone, we receive about 9.5 million returns annually. It is not possible to assess all of them manually. Because of the scale of our work, we use algorithms in many of our processes and across multiple tax types. This helps us process these large numbers and make decisions.

Tax and Customs Administration algorithm register

Through the algorithm register, we aim to be open and transparent about algorithms we use and for what purpose. We include the Tax Authority's algorithms in this register that directly or indirectly affect citizens or businesses. For example, algorithms that:

• advise on decision-making or
• select which returns are processed automatically and which are checked manually.

Algorithms that are literally taken from the law we do not include in the register. For example, algorithms on how to calculate the amount of tax to be paid or received back.

Laws and regulations

When we use data and algorithms, we comply with applicable laws and regulations. For example, there is the General Data Protection Regulation (AVG) to protect the privacy of citizens and entrepreneurs. Various regulators also regularly check whether we still comply with applicable laws and regulations. For example, the Audit Service Rijk (Central Government Audit Office), Court of Audit and the Personal Data Authority.