Hmmm ...
* governments want to improve public health
* parents in a given geographic region can opt-in on birth of a child to enroll their child in a longitudinal data-gathering regime
* parents' and child's PII (personally identifiable information) is stored in a special private Fluree instance (or other DB), and each is assigned UIDs that can be public without disclosing their identity
* the child's UID, along with basic demographic info (that can't be used to resolve their identity) is pushed to the public Fluree DB ...
* some info, such as genetic profile, very specific outcomes of educational tests, etc., might be stored over time in a very secure DB not open to the public
* basic measures of health, education, nutrition, could be stored publicly and available to researchers ... with more and more info stored over time
* more info about a child's "history" that might be useful in correlating with positive / negative outcomes also might be stored publicly
* public health researchers could analyze trends, etc., to determine what education and nutrition programs, environments, etc., contribute positively to good outcomes
* public health and other researchers, such as medical, pharma, nutrition, etc., researchers, could use public data to find "cohorts" of children that might be suitable for studies ... and reach out in the system to families (whose identities will not be disclosed until appropriate) of those children to give them more info about why their child should become part of a study, and give them a chance to opt-in or contact researchers for more info
That's just one very interesting application off the top of my head, and Fluree (I'm not associated), as a Public Benefit Corporation (PBC) who states they eventually plan to open-source all or much of their technology, might be a good venue in which to deploy such a system ... a system that would require high levels of confidentiality, trust, while still being open to the extent possible and advisable.