Ever since the Nuremberg Trials put on display the atrocities of human experimentation at the hands of Nazi doctors, the concept of informed consent has been a cornerstone of both medical treatment and biomedical research.  Although no country has adopted the Nuremberg Code in its entirety, most Western nations have acknowledged the importance of informed consent as a pillar of research and medical ethics. But if study participants or patients don’t understand the documents that describe the study protocol or treatment plan, are they truly informed?
For human research subjects, the U.S.’s Code of Federal Regulations states:
46.116 General requirements for informed consent
Except as provided elsewhere in this policy, no investigator may involve a human being as a subject in research covered by this policy unless the investigator has obtained the legally effective informed consent of the subject or the subject’s legally authorized representative. An investigator shall seek such consent only under circumstances that provide the prospective subject or the representative sufficient opportunity to consider whether or not to participate and that minimize the possibility of coercion or undue influence. The information that is given to the subject or the representative shall be in language understandable to the subject or the representative. [Emphasis added]
In “Public Health Literacy in America: An Ethical Imperative,” Julie Gazmararian and her co-authors note that one of the “Characteristics of a health-literate America” is that “Informed consent documents used in health care are written in a way that allow people to give or withhold consent based on information they need and understand.” 
Unfortunately, actual informed-consent materials fall far short of promoting understanding. Informed-consent documents are used both for legal reasons and to explain research or treatment protocols; as a result, they’re susceptible to being filled with legalese and medicalese—the worst of both worlds. Giuseppina Terranova and her team reviewed consent forms used in various imaging procedures and found that
At qualitative assessment by consensus of the expert panel, the informed consent forms were complex and poorly organized, were written in a jargon style, and contained incomplete content (not including information about treatment options, long-term radiation risk and doses); for outcome probabilities, relevant information was not properly highlighted and easy to find. 
Having a complex informed-consent form rife with legalese only stirs distrust among participants and patients. In “Improvement of Informed Consent and the Quality of Consent Documents,” Michael Jefford and Rosemary Moore write:
Informed consent has two main aims: first, to respect and promote participants’ autonomy; and second, to protect them from potential harm. Provision of information in an understandable way lends support to both these aims…
The written informed-consent document (ie, consent form) is an important part of the requirement to disclose and advise participants of the details of a proposed trial. Although the form has been said to give “legal and symbolic documentation of an agreement to participate,” the length and complexity of informed-consent documents hinder participant understanding. Viewing the consent form mainly as a legal document tends to hinder attempts to create reader-friendly documents: “many sponsor and institutions appear to view them primarily as a legal instrument to protect them against litigation.” 
Ironically, “The high reading levels of most such forms precludes this understanding, increasing rather than limiting legal liability.”  What’s more, if a consent document is hard to understand, research participants will believe researchers are merely covering their own asses rather than prioritizing the participants’ well-being.
The obvious solution to this problem is to use plain language in informed-consent documents. In a test of a standard versus modified (plain language) pediatric consent form for parents, Alan R. Tait and co-investigators found that
Understanding of the protocol, study duration, risks, and direct benefits, together with overall understanding, was greater among parents who received the modified form (P<.001). Additionally, parents reported that the modified form had greater clarity (P = .009) and improved layout compared with the standard form (P<.001). When parents were shown both forms, 81.2% preferred the modified version. 
Further, not only do plain language statements (PLS) protect research subjects and patients, but they also benefit researchers:
In the most practical sense, a commitment to producing good quality PLS leads to faster ethics approval—an outcome that will delight researchers. However, the real reward that comes with commitments to high quality PLS is the knowledge that parents and participants are properly informed and that researchers are contributing to a positive change in meeting the information requirements of parents and young research participants.
Plain language information statements need to be clearly understood by research subjects if the ethics process for research approval is to fulfil its objective. 
I see an opportunity for plain language experts to advocate for informed consent by promoting clear communication principles at research institutions and health authorities. Although most institutional research ethics boards (REBs) have guidelines for consent forms that recommend using lay language, I would guess that most REB members are unfamiliar with the plain language process. Institutional REBs, such as the one at Simon Fraser University, consist of not only faculty members and students but also members of the wider community, so even if you are unaffiliated with the institution, you may still be able to join an REB and advocate for plain language from the inside. If you’d rather not commit to sitting on an REB, you might want to see if you could give a presentation at an REB meeting about plain language and clear communication principles.
In my ideal world, a plain language review of consent documents would be mandatory for ethics approval, but biostatistician and current chair of SFU’s REB, Charlie Goldsmith, warns that adding a further administrative hurdle to ethics approval probably wouldn’t fly. Most researchers already see the ethics review process as burdensome and a hindrance to their work. But if you could convince researchers that a plain language review before submission to the REB could accelerate approval, as Green and co-investigators had found, you might help open up opportunities for plain language advocates to work with researchers directly to develop understandable consent documents from the outset.
That said, plain language informed-consent forms address only one facet of the interaction and relationship between researcher and study participant, or between clinician and patient. Jefford and Moore write:
There are reasons for putting effort into the production of plain-language participant information and consent forms. However, evidence suggests that these forms should not be relied on solely to ensure that a person understands details about a trial. Plain-language forms should be seen as part of the process that aims to achieve meaningful informed consent. 
In other words, clear communication initiatives should extend beyond written materials to in-person interactions: researchers and clinicians should receive training in plain language debriefing and in techniques such as “teach-back” (asking someone to repeat the information they’ve just been given in their own words) to ensure that they are fulfilling their ethical obligations and are doing all they can to help patients and study participants become truly informed.
To learn more about research ethics, including informed consent, take the Course on Research Ethics, developed by Canada’s Panel on Research Ethics.
 JB Green et al., “Putting the ‘Informed’ into ‘Consent’: A Matter of Plain Language,” Journal of Paediatrics and Child Health 39, no. 9 (December 2003): 700–703, doi:10.1046/j.1440-1754.2003.00273.x.
 Julie A Gazmararian et al., “Public Health Literacy in America: An Ethical Imperative,” American Journal of Preventive Medicine 28, no. 3 (April 2005): 317–22, doi:10.1016/j.amepre.2004.11.004.
 Giuseppina Terranova et al., “Low Quality and Lack of Clarity of Current Informed Consent Forms in Cardiology: How to Improve Them,” JACC. Cardiovascular Imaging 5, no. 6 (June 1, 2012): 649–55, doi:10.1016/j.jcmg.2012.03.007.
 Michael Jefford and Rosemary Moore, “Improvement of Informed Consent and the Quality of Consent Documents,” The Lancet. Oncology 9, no. 5 (May 2008): 485–93, doi:10.1016/S1470-2045(08)70128-1.
 Sue Stableford and Wendy Mettger, “Plain Language: A Strategic Response to the Health Literacy Challenge,” Journal of Public Health Policy 28, no. 1 (January 1, 2007): 71–93, doi:10.1057/palgrave.jphp.3200102.
 Alan R Tait et al., “Improving the Readability and Processability of a Pediatric Informed Consent Document: Effects on Parents’ Understanding,” Archives of Pediatrics & Adolescent Medicine 159, no. 4 (April 1, 2005): 347–52, doi:10.1001/archpedi.159.4.347.
 JB Green et al., 2003.
 Michael Jefford and Rosemary Moore, 2008.
This post is an excerpt (heavily edited to provide context) of a paper I wrote for one of my courses about the role of plain language in health literacy. Plain language experts might find some of the references useful in their advocacy work.