In the last two months, you might have noticed a small pop-up at the bottom of your Castor EDC study that looks like this:

This question is a commonly used method to measure the loyalty of users, which in turn reflects their satisfaction with the product. Users can give a rating between 0 and 10 and the overall user rating will be calculated in the form of a Net Promoter Score (NPS).

The NPS is calculated by first dividing the responders into three groups:

  • Promoters: users that rate the product with a 9 or 10.
  • Passives: users that rate the product with a 7 or 8.
  • Detractors: users that rate the product with a 6 or below.


The total percentage of detractors is then subtracted from the percentage of promoters, yielding the NPS (hence the name ‘net promoter score’), which can range from -100 to +100.

Such a quantification enables us to monitor trends of customer satisfaction with Castor EDC. If the NPS drops, we try to identify the main reasons and take measures to improve it, such as develop certain functionalities that are often requested. We can also see what promoters like about our product and make sure to maintain and improve those features.

Therefore, every three months you will receive this popup asking you to rate Castor EDC. It is possible that you also occasionally receive an email requesting to give us short feedback.The feedback that we receive is essential for us to improve the product. We would be grateful if you could take the time to do this!

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