Since project providers know the target group on which their projects will be focused, is it possible to collect sensitive personal data for common output indicators (e.g. migrants, people from foreign background, minorities) based on estimate figures?

No. The obligation to collect and store data on individual participants in operations (micro-data) also covers sensitive personal data; there is no derogation in this sense foreseen in the regulations (Regulation (EU) No. 1303/2013 and Regulation (EU) No. 1304/2013). Estimates based on the opinion of project providers will not be accepted.