Background

MedCredits is a decentralized platform that connects patients to physicians for healthcare services. During the development of our teledermatology dapp, it became clear that one of the major difficulties with a decentralized platform is the on-boarding of licensed physicians without relying on a central party.

Traditional telemedicine services (such as Teladoc or First Derm) use their own workforce to onboard physicians by reviewing credentials and maintaining an internal database. Early on, we knew that a major part of our token design would center around incentivizing this work. Our initial instinct was to approach verification of physician credentials as an oracle dilemma in which token-holders would report on features of physicians’ professional qualifications similar to reporters in Augur. It was then that we came across the adToken whitepaper which described a bonding/challenge crypto-economic design known as a token-curated registry (TCR). My favorite explanations of TCRs are Mike Goldin’s initial blog post on the subject, and Simon de la Rouviere’s subsequent analysis. MedCredits uses a token-curated registry as a solution to physician on-boarding.

The MedCredits TCR involves an incentive game in which doctors seek entry to the physician registry in order to be granted the privileges of being a physician in the ecosystem including access to patient case data. Verifiers review these applicants and challenge any who they believe to be nefarious (i.e. not a real doctor). Token value increases if patients can trust the registry and use the services provided by the physicians. This incentivizes verifiers to curate a high-quality registry containing only real doctors. The basic workflow is as follows:

Applicants to the registry submit images of their medical diploma, medical license and board certification diploma along with a deposit of MEDX tokens. They also fill out a registration form which includes metadata fields such as: address of practice, specialty, country/state of accreditation etc. Applicants then undergo a challenge period whereby anyone holding the MEDX token can review the submitted data and challenge the applicant by matching their MEDX deposit. If no challenge is raised during the challenge period, the physician is added to the registry and their metadata is stored with a hashed reference. If a challenge is raised, then a voting period begins in which all other MEDX holders may participate in a vote. The outcome of the vote determines if the applicant is admitted to the registry or if they are deemed nefarious.

Following the vote, tokens are re-distributed as follows:

If the vote favors the applicant, the challenger loses her deposit and the minority voters lose a portion of their deposit. These tokens are given to the applicant and majority voters. If the vote disfavors the applicant, the applicant loses her deposit and the minority voters lose a portion of their deposit. These tokens are given to the challenger and majority voters.

Identity, Metadata and Governance

A major difference between the original adToken TCR and MedCredits’ implementation is that the individual submitting the application must certifiably be the individual seeking admittance to the registry.

This, of course, requires that an applicant verify that the Ethereum address from which they send the application transaction is associated with their public identity. This can currently be done through trusted third parties such as government officials or through creative cryptographic proofs.

There are two important implications when the applicant to the registry is the same entity submitting the application. First, the registry can reliably collect associated metadata. In the case of a physician registry, this may include physician’s specialty, office number, professional e-mail, office address, country/state of accreditation. Physicians would have the ability to revise this metadata at any time without jeopardizing their status in the registry. This is powerful because it significantly expands the types of applications that can be built on top of such a registry. Second, if any governance or polling is desired, this ensures that a member of the registry can only cast a single vote. These types of TCRs effectively allow undifferentiated ethereum accounts to differentiate into domains that are significant to society. For example, it is reasonable that physicians should have a collective voice in the governance of our healthcare systems. One particularly intriguing application is Delphi which uses a TCR to onboard arbiters who can then go on and adjudicate any disputes in a decentralized marketplace for freelancers. One can envision how a similar model can call upon physician arbiters to audit any disputes in an otherwise open market for healthcare services and data.

Why create a public physician registry?

There are short-term and long-term goals to such a registry. In the context of our dapp, traditional telemedicine companies cannot scale. By centralized standards, Teladoc’s national network of over 3,100 doctors is impressive. A permissionless, crypto-economically incentivized TCR has virtually no upward limit in scalability of the operation. What’s more, the work of reviewing credentials and on-boarding physicians will be done at minimum marginal cost.

However, the use-cases of a public, decentrally-curated physician registry are vast. Associated metadata could easily be used to implement a rent-free version of zocdoc.com. The physician referral portal in the teledermatology dapp uses this metadata to refer appropriate telemedicine consultations to local physicians. Practice patterns could be polled by practice location. Physicians could pool funds into multisignature contracts that provide collective malpractice insurance coverage. The physician registry is open-source and can be called by any application that requires a pool of licensed physicians. Tele-dermatology is a deliberate go-to-market strategy that works within the current state of dapp development infrastructure and still delivers a usable product that will attract physicians and patients to the network. It is not the end game.

Even more intriguing are the implications such a registry bears on the global state of healthcare. Physician burnout now exceeds 50% as physicians have progressively seen their practice autonomy diminish. Insurance companies demand increasingly detailed documentation prior to paying out and physicians who entered the profession hoping to provide high-quality patient care are now spending over half their time as data-entry technicians. Physicians are being commoditized and have lost the ability to self-govern the value of their professional services. US healthcare costs continue to rise faster than inflation as government and institutional involvement debilitates free-market dynamics. Cryptographically secured networks make new forms of peer-to-peer commerce possible and stand to replace these costly intermediaries. A public, decentrally-maintained physician registry is a necessary substrate for these networks and can give rise to decentralized healthcare organizations.

In conclusion, MedCredits is creating the first global, decentralized registry of physicians. The MEDX token is used to power a token-curated physician registry. This registry can scale globally and will initially power our teledermatology dapp. It can also be used to build any 3rd party dapps that require licensed physicians. The registry empowers physicians to self-govern their services and can form the foundation of a new peer-to-peer model for the healthcare industry.