User-facing informational report alongside outputs

[benbc]

Logging for the Cohort Extractor includes information that is only of interest to a developer trying to debug the system and also some information that may be of interest to researchers to help them understand their results and the behaviour of the study. Researchers can only access the logs by connecting to the server.

It would be helpful to separate the researcher-useful logs into a separate report that is more easily accessible. Ideally it would go back to the Job Server so it could be read alongside the status of the jobs, but this would need to be dealt with carefully to avoid security risks.

An example of the kind of information that would be useful is details of when small number suppression has been applied (for example here).