When the SOM survey is distributed, your address is obtained from the population register. In some instances, your phone number may be obtained from public registers. This data is only used in order to send you information about the survey. Once you have completed the survey, the combination of numbers on the front of this letter will be registered. This ensures that you will not be sent any unnecessary reminders. During the course of the survey, we do not have access to your contact details, therefore you will need to refer to the number combination on the front of this letter when contacting us. All address data will be completely deleted when the study is finalized, and only then will we compile the responses.