How Klingel has improved the quality of its customer database and reduced the number of postal returns and incorrect addressing


Daily events affect the quality of the customer data. Up-to-date and correct customer data is a prerequisite for good business operations. In this case, we highlight how Klingel can communicate more effectively and efficiently thanks to correct and up-to-date customer contact details.

The challenge: a daily changing customer database

Michael Labourel from Klingel: “Our goal is to keep our database 'ACCU': Actual, Correct, Complete, and Unique. This way, we can serve our customers better and save on returns due to incorrect addressing.”

Due to the extensive range and international coverage, Klingel appeals to a large target group and the webshop contains a lot of customer data. Keeping this information up-to-date is essential for effective customer communication. The challenge here is that the customer database changes daily due to events such as relocations and deaths.

Based on the needs of Klingel, a quality check of the customer data has started. For example, a quality analysis and baseline measurement were carried out and attention was paid to the topicality and correctness of the customer data.


Before an organization can start improving data quality, it is important to know where they stand. Therefore, a baseline measurement was carried out for Klingel: mapping the current quality of the customer database. A joint inventory was created with the available data and a data quality analysis was performed on 100.000 records. This provided insights into, among other things, the following elements:

• Spelling of the surname
• Correctness of addresses
• Relocations
• Deaths
• Registration ‘Bel-me-niet Register’


Klingel maintains a transaction date in the customer database. This is the date on which a customer was last contacted. This date has been used as a basis for checking which data is the most up-to-date: Klingel's customer data or EDM's reference data.

Michael Labourel: “Delivering the data was a time-consuming job for us, with a lot of internal contact, especially on our side, about how the file should be delivered. My advice is to coordinate this well in advance, also internally.”


To determine the correctness of all Klingel customer data, after the testing phase, the complete Klingel customer database was again compared with the EDM reference database. Various elements were used to test the extent to which the data was ‘correct’ and could be processed. The data scaled under the ‘doubt’ and ‘uncertain’ categories was manually checked.

Stefan Elsendoorn, data quality consultant at EDM: “Due to the tightening up of the business ruling, only a small part of the customer database remained, which was eligible for an additional manual check by Klingel employees.”

Direct mailing to customer groups
To measure whether EDM's data quality solution improved the accuracy and topicality of the customer data, Klingel chose to send a direct mail to the various customer groups. The number of postal returns was an important indication of the improvement.



One of the findings from the testing phase is that there was a high number of deaths and a significant number of relocations. Based on these results, the best approach for the other customer groups was determined and the first impetus for the business ruling was made.

Decrease in postal returns and reduction in incorrect addressing 

Because Klingel gained more insight into which postal items would not arrive at customers due to relocations or death, they were able to save considerably on printing and shipping costs. In addition, the number of postal returns decreased from a total of 1,3% in 2018 to 0,27% in 2019.

Improved data quality, strong foundation for the future

Klingel has created a strong foundation with the improved data quality to build on in the coming years, with annual savings on unnecessary costs. The next step is the same data quality analysis for Klingel in Belgium: EDM also offers data quality services in Belgium.

Michael Labourel: “The collaboration with EDM is going as desired. In terms of communication, things are going really well, and its people are always available. The start-up year was a difficult one because the file to be delivered had to go to various people internally at our place and this was regularly delayed. However, this did not have anything to do with EDM. I am satisfied!”

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