&gt;&gt;nobody was willing to give up any data, fearing they would lose their own value in the system<p>I suspect this is correct, particularly between the insurance companies and the providers.  The coding of what exactly was done directly drives the reimbursement that the providers get.  Thus, there&#x27;s a clear incentive to be opaque and show the insurers only what you need to.  Sometimes for good reason (insurers denying coverage solely for cost reasons), sometimes not (billing fraud).