Simplesat surveys include an invisible tracking pixel embedded in your surveys that detect each time your customer opens an email.
We use this data to calculate the response rate. When the tracking pixel is triggered (image downloaded), we conclude that the survey was opened. The response rate is calculated by:
Response Rate = (# of opens) / (# of responses received)
Note: The response rate percentage is just an approximation of how frequent your clients open the email as they have a way of previewing the email without being detected by the tracking pixel.