Summary: HL7 is a closed standard; HL7 claims to require (expensive) membership to implement its standards, including CDA; the Oracle v. Google ruling that API's are not protected by copyright suggests that HL7 may have no legal basis to prevent implementations by non-members or to extort a fee; but until this is clarified, perhaps CDA should be avoided in lieu of more open alternatives.
Unlike the DICOM standard, whose governing body requires no fee for implementation, the HL7 family of standards (including V.2, V.3 and CDA, amongst others) are not "open standards" in this respect. In particular, the HL7 organization that publishes the standards currently states quite explicitly that organizational (not individual) membership is required in order to "use the material" (HL7 International IP Policy). The cost is decidedly non-trivial, requiring a continued annual contribution of between $1260 - $19,635 (HL7 Membership).
There is not universal consensus about what exactly the definition of an "open standard" is, and how it relates to the matter of fees; this is well summarized in the Wikipedia entry on the matter. Fees for use can be needed in two contexts, as fees to the organization in control of the standard, and as royalty-fees for patents. The European Union definition, for example, precludes the charging of fees of either type; the same goes for the Open Source Initiative's definition, which further requires that the standard also be freely available.
Since many (if not the majority) of contributors to activities like DICOM, HL7 and IHE are large organizations, and since the membership or fees demanded by HL7 pale in comparison with other costs (like that of EHR certification for Meaningful Use in the US), this has not been a very big concern to decision makers. Just as most global technology companies are not that concerned about patent issues, being participants in patent portfolio sharing cabals, it has sometimes been difficult to promote the case for openness, when a conflict with convenience or expediency arises. As a consequence, the criticality of this issue for open source software developers, non-profit organizations and small users is routinely overlooked.
CDA is a case in point; both IHE, and more recently DICOM, have been nonchalantly pursuing a course of encouraging the use of CDA, and developing profiles (or what HL7 calls "implementation guides") that rely on the underlying CDA mechanisms, without some of us realizing, frankly, that we were building upon an inherently closed standard. The problem has been compounded by the adoption by the ONC Healthcare IT Standards Committee in the US (in the context of Meaningful Use), and in other activities like the European cross-border epSOS pilot project. Indeed, the ONC Proposed Rule for the Phase 2 of Meaningful Use contains language that would preclude the use of "competitors" to CDA for encoding of patient summaries (you recall the bitter fight between HL7 and ASTM over CCD versus CCR).
What HL7 International thinks about the interpretation of their IP Policy with respect to CDA implementation is explicitly reiterated in this response, "Questions & Answers on the use of HL7 CDA and required licensing".
Obviously, it would be unfortunate if there was to be discrimination in the market place against smaller participants (both implementers and users), as a consequence of imposing a mandatory requirement to use fee-based standards. Surely this is not the intent of the policy makers; perhaps they may not have been sensitized to this concern, though this would be surprising, given the sophistication of the stakeholders.
I am not involved in HL7 politics or administration, so I have no insight into their motivation or their future plans. I have heard that they are considering changes to their policy, but whether it is to make things better and relax these constraints, or to make things worse in order to maximize their revenue stream, I have no idea.
Some folks pointed out to me though, that there may be hope, regardless of HL7's intent or desire, in the form of the recent order from the court in the case of Oracle v. Google. You may recall that this litigation was in part related to the independent Android implementation of a sub-set of the documented Java API's provided by Oracle. A copy of the order itself is available as document "Case3:10-cv-03561-WHA Document1202: Order Re Copyrightability of Certain Replicated Elements of the Java Application Programming Interface". Commentary on it can be read in several places, such as in John Harris's article "Judge in Oracle v. Google Case Rules that APIs are Not Copyrightable", in which he notes "... this is not really a new result ... this has been the law for quite some
time, until the API copyrightability question was squarely raised in
this case". The question of what subject matter is or is not copyrightable in the US is apparently explicitly defined in "17 USC § 102 - Subject matter of copyright: In general", which states in (b) "in no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work".
That definition would seem to squarely encompass standards like HL7, including CDA; though I am no lawyer, and have not consulted one, it would reassure me if were planning on implementing any part of HL7 in my own open source code, or using someone else's implementation in a production environment, and couldn't justify the non-trivial expense of joining HL7 as an organizational member. I am not sure wherein lies the legal basis of HL7's claim of a right to restrict the "use of the material".
That said, since there are truly open alternatives to CDA, until HL7 clarifies the situation in a satisfactory manner, should one consider avoiding CDA altogether? After all, regardless of the merits of any legal question, one hardly wants to get in a legal wrangle with a large organization, and since the policy makers at a national level seem to have abrogated their responsibility to select only open standards, it males sense to look for alternative standards that are open.
Since the standards for the "payload" can largely be separated from standards for the exchange and workflow management, (e.g., XDS, XDR or DIRECT are just useful for PDF, text, or any XML document, not just CDA), there is an opportunity to jump off the CDA bandwagon (juggernaut). Indeed CCR was just such a deviation (that the HL7 folks would no doubt was rather forgotten about sooner rather than later).
One interesting possibility is the CE/ISO 13606 (OpenEHR extract); since this is an ISO standard, it is not free to obtain the specification from CEN or ISO (like HL7 and ASTM, CEN and ISO also charge for copies of their standards, unlike DICOM, IETF or W3C), but it is free to implement, and (unofficial) XML schemas can be obtained from the EN 13606 Association website, and "last drafts" of the CEN standards may be available with a Google search. Charging a "nominal fee" for access to the text of a standard is permitted by some Open Standard definitions (such as in the European Interoperability Framework) though not others (such as the Open Source Initiative). There is an insightful UK NHS Connecting for Health report about "Investigating implementing CEN 13606 with HL7 V3 and SNOMED CT".
Since I am not really involved at all in this EHR and CDA stuff, and my primary interest remains radiology imaging and hence the imaging report, I cannot speak to the practicality of CDA alternatives, and to what extent the issues may be, but they certainly seem to be worth exploring.
This matter of HL7 fees for use came up at a DICOM WG 10 (Strategic Planning) meeting recently; a summary of the discussion can be found in the minutes. Not recorded in the minutes, but identified by one participant, was the need for care with respect to contributing material developed in a DICOM context (such as radiology report templates), that was then made available to HL7 for joint publication; at the very least, any material developed on the joint DICOM-HL7 group, WG 20, should be accompanied by language indicating that it must remain free for use and cannot be restricted by HL7 when jointly published. Likewise, though DICOM WG-8 has been encouraged to focus its report template standardization efforts related to the RSNA reporting initiative, on CDA encoding, this position may need to be either reconsidered, or the templates produced in a manner such that they can be encoded in other open standards rather than CDA.
At a national level, this is similar to the problem with SNOMED, which also was not "free" for general use; again one wonders whether they have the legal right to restrict use, since SNOMED is all about "concepts", which are explicitly excluded from copyright protection under 17 USC § 102. Regardless, for US use, the NLM "paid them off" with a $32.4 million five year license (them being CAP), and now pays an annual fee of about $6 million to IHTSDO, which now owns SNOMED. My reason for mentioning this, is that it may have set a precedent for well-established closed standards organizations extorting non-trivial sums of money from national governments, and perhaps that is what HL7 International is hoping for. It also doesn't help international users.
From my perspective, the best outcome would be for HL7 to back away from this position, and to allow anyone to implement any of their standards royalty-free anywhere. Indeed, anything less than that would seem to me to be a strong incentive to lobby against using CDA at all, and seeking out a replacement.