There are sometimes ethics rules on how long data is stored for. If there's a commitment to destroy the raw data after a period, eg. five years, often it can't

There are sometimes ethics rules on how long data is stored for. If there's a commitment to destroy the raw data after a period, eg. five years, often it can't be publicly released (even anonymised) or there'd be no way of ensuring it's been destroyed when the time is up.