Alan,
Thanks for your note. I can't tell if you are responding or had seen the note I sent several hours ago. In that note, I said differentiated access is essential and we must include it in our thinking. I pointed out that trying to design access to public data under the assumption, either implicit or explicit, that differentiated access will not exist leads to a design that is poor in multiple ways.
One key point I did not cover in the memo is the distinction between differentiated access as a concept and SSAD as a particular proposal for achieving some aspects of differentiated access. As we have heard, there are criticisms of the proposed design and significant open issues that have not yet been addressed. Among the open issues, the most important is fleshing out the matrix of purposes, groups intended to have access for each purpose, the data elements they should receive, and performance requirements. The overwhelming proportion of requests will have to be satisfied quickly and automatically. Manual review is tolerable for only a small fraction of the total set of requests. The best way forward, in my view, is to tackle the open issues. That's apparently outside the scope phase EPDP 2A, but I think it is very much within scope to be clear that this is a requirement.
Thanks,
Steve