The evaluation of patient outcomes in the American Academy of Family Medicine's National Demonstration Project (a.k.a. 'TransforMED' project) is written up by Jaen et al in the Annals of Family Medicine supplement here.
This projected included a terrific evaluation team that really dug into a broad swath of data to understand the impact on patients. They measured patient experience of care with the core attributes of primary care: access, relationship, care coordination & comprehensiveness of services, as well as a number of indicators of chronic disease management.
I want to point out a very common misconception in the office practice communities: "Doing Open Access" is meaningless unless your patients report that their access has improved. The industry standard of "number of days to third available appointment" with "future fill rates" are proxy measures. They mean nothing if the patients in the practice report that their access has gotten no better.
After learning from the masters (Murray & Tantau) and implementing advanced access in my own practice, I have helped many achieve dramatic improvements in access and was one of the IHI faculty teaching this intervention to hundreds of practices from around the U.S. There are a hundred ways to make the proxy data look good but accomplish nothing meaningful from a patient's perspective.
"We can see you today but you won't be able to see your regular PCP" is a fail because we trash one pillar of primary care to support another.
Making "Number of days to third available" go to zero by essentially cooking the schedule books is a fail.
Access success is not achieved when "sure we can see you today" is coupled with "But we run out of appointments by 11AM."
It is possible to truly improve access and to know with confidence that the improvement is real. The way is to ask the patients in the practice to report on their experience with access. Patients are the ultimate arbiter of access success/failure. Populations of people who have good access are less likely to skip needed appointments, are more likely to follow up with their chronic condition follow-up appointments, are less likely to end up in the emergency room and are less likely to be hospitalized.
Patient experience of care with access is hard wired to meaningful outcomes as noted above.
Our industry has lost sight of the meaning of our work when we credit ourselves with success for things that have no meaningful impact on the lives and health of those we serve.
The AAFP's NDP/TransforMED project has demonstrated that their high cost/low relative value approach is not a path likely to lead our nation to the kind of robust primary care we need so that we can become a high performing health system. At this point any large purchaser of health care or agency that funds improvement & innovation ought to be surveying the field for other paths, ones lined up with meaningful improvements in patient experience of care measures linked to important outcomes.