We are updating our measurement system
The e-commerce market is developing rapidly and offers increasingly more opportunities. That's why we are updating our measurement system for advertising and e-commerce data, according to IAB Europe standards. This provides sharper insights and better comparability with other platforms. Your results may change slightly as a result. The update impacts the data in your seller account(s) and your advertiser data. Read here what this means for you and what steps you can take.
When will you see this data change?
- Seller account: 6 January
- bol API: 6 January
- Branded Shelves: 13 January
- Managed Advertising Services: Onsite/Offsite Display and Social campaigns: 28 January
- Supplier account: 16 February
What does this mean for your seller account?
We are measuring customer behavior on our platform in a new way. Search volumes and customer visits on item and landing pages may therefore differ slightly from before. This will also automatically influence your conversion, buy box percentage* from early February also your item positions, because these values are calculated based on your customer visits. In addition, we will now also measure customer visits for second-hand and refurbished items. Because the data will be measured differently from January 1, 2026, you may see a trend break compared to previous years.
*Please note, we are referring to the 'buy box percentage', which is the percentage of time your offer has been in the buy box in the past 28 days. This value is therefore influenced by customer visits. This new measurement system does not affect the factors that contribute to the buy box.
What can you do?
- Download 2026 data again: have you already downloaded data from 2026 in the past few days? Please download it again. On January 6, we switched to this new measurement system, but the data has been adjusted retroactively from January 1, 2026.
- Historical data remains as is: data from before 2026 will not be adjusted to the new measurement system. Data from previous years remains as it is, so you do not need to download it again.
- Compare again: when comparing data, consider a possible trend break between previous years and 2026.
Do you not use bol's seller account, but an API? Then check the Developers platform for more detailed information.
Are you also a supplier?
Are you also a supplier via bol in addition to being a partner? From February 16, the new measurement system will also apply to the data in your supplier account. Just like in your partner account, search volumes and customer visits on item and landing pages will be measured differently. This will, among other things, affect your visits and conversion reporting. With this adjustment, the data in the supplier account will also match your partner account. How convenient!
What can you do?
- Download 2026 data again: have you already downloaded data from 2026 in the past few days? Please download it again. On February 16, we switched to this new measurement system, but the data has been adjusted retroactively from January 1, 2026.
- Historical data remains as is: data from before 2026 will not be adjusted to the new measurement system. Data from previous years remains as it is, so you do not need to download it again.
- Compare again: when comparing data, consider a possible trend break between previous years and 2026.
What does this mean for Advertising via bol?
From January 13, just like with Sponsored Products, we are also switching for Branded Shelves. On January 28, all Managed Advertising Services (such as Onsite Display, Offsite Display, and Social campaigns) will follow. With this new measurement system, you can better compare and evaluate advertising results across different channels. In the coming weeks, your results may change because we are using new definitions for interactions (such as clicks and impressions). This may result in a trend break.
What can you do?
- Review your benchmarks: do not compare your performance one-to-one with previous periods, but look at trends within the new measurement system.
- Monitor your campaigns: pay attention to shifts in clicks, CTR, conversion rates, and ACoS.
- Adjust your targeting and budgets where necessary: clicks may shift between page types. Use the new results to improve your campaigns and continue to aim for the best possible result for you.