I’m one of the people that will be using this data
Its certainly the case that the NHS cohort data is close to unique in terms of richness and value. Many patients would be happy to share their records for the purpose of research if they were asked and if there were guarantees about no further use without further permissions.
Regarding DV, usually sensitive codes like that are removed from records prior to being shared, but it’s worth contacting NHS digital to check as I can’t say for sure that’s the case here (although I will be very shocked if they aren’t)
Be shocked. NHS Digital is exempt from the standard privacy legislations such as GDPR so are not required to redact. There was good reason for this - tightly controlled data sets with limited users in approved research establishments was the alternative to restricting the data with standard privacy rules.
Pseudonymised data by its very nature is reversible. Only for legal reasons? Well who knows what will be legal in the future. Possibly a commercial contract, DWP, handing the longitudinal record over to Palantir/other commercial interests for track and trace or simply marketing? Its certainly a massively money spinning cohort of data.
Lets say there is a degree of pseudonymisation, some flags are removed. Cross match with commercially available data sets of social media usage, marketing sets, retail sets, census data (commercial orgs can buy it by postcode) and its not difficult to home in on individuals.
This isn't new - it was niche 10 yrs ago when the forerunners of companies like Cambridge Analytica were speaking on the fringes of tech conferences; telling you were you were yesterday at 10:00 as a party trick to show off their data matching. Now its mainstream and its cheap.
Its outrageous that the population of E&W is being opted in to a system allowing commercial sell off of their most sensitive data without even discussion let alone informed consent about the use of their data or where any commercial revenue ends up.
So if you want the data available for research don't shut your eyes to the privacy issues - lobby for proper consent and information.
In the mean time, I've opted out as have all my family and colleagues and their families.
Oh and you must fill in both the forms, including one on paper and they go to two different places. No publicity, difficult to opt out. Anyone would think they had something to hide.