Plain Language, Readability, and Accessibility

Plain language enables the intended reader to find, understand, and use information. It is not childish language, a shorter technical abstract, or a readability score. In medicine, plain language must preserve evidence, uncertainty, risk, and the boundary between general information and individual advice.

Begin with the reader's decision

Define the audience more precisely than “the public.” A trial participant, person considering consent, patient living with a condition, caregiver, journalist, policy audience, and reader of a publication summary have different questions and consequences.

Ask:

• What does this reader already know?
• What do they need to decide, understand, remember, or do?
• What may frighten, confuse, stigmatize, or falsely reassure them?
• Which languages, literacy levels, disabilities, devices, and settings shape access?
• Which information is essential for a safe action?
• How will understanding be tested with intended users?

Organize around those questions. Put the conclusion or action close to the information that supports it. Build navigation that lets a reader find purpose, benefits, risks, choices, practical steps, uncertainty, and sources.

Translate meaning, not terminology alone

For each technical idea, decide whether to:

• use an everyday term;
• use the technical term after a plain explanation;
• define it in place;
• show it with an example or visual;
• remove it because it does not serve the reader's task.

Keep necessary medical names where they help readers talk with clinicians or locate reliable information. Define them on first use and keep the same term thereafter. Avoid rotating through synonyms merely for style; in patient material, consistency supports comprehension.

Use familiar words and concrete verbs. Prefer “take” to “administer” when the meaning allows, and “high blood pressure” with or before “hypertension” when the audience needs both. Explain nominalized phrases as actions. Replace vague references such as “this may occur” with the event that may occur.

Control sentence and paragraph load

Shorter sentences can help, but sentence length is only one part of difficulty. A short sentence can still contain an unfamiliar concept, hidden condition, ambiguous pronoun, or dense number. Keep one main idea per sentence when possible. Place conditions next to the action they control. Use active voice when the actor matters and passive voice when the actor is unknown, irrelevant, or appropriately backgrounded.

Use headings that answer reader questions. Keep paragraphs focused. Lists help with steps, choices, symptoms, or parallel facts; they do not automatically clarify a complicated argument. A document with many bullets can still hide priority and causality.

Explain numbers as decisions, not ornaments

Many readers struggle with probability, percentages, ratios, and changing denominators. Good risk communication:

• uses a consistent denominator when comparing groups;
• gives natural frequencies where useful, such as “3 out of 100”;
• distinguishes absolute and relative change;
• states the time period;
• identifies the population;
• presents benefit and harm with comparable framing;
• avoids switching between survival and mortality frames to make one option look better;
• explains uncertainty and the limits of prediction for an individual.

A change from 1 in 100 to 2 in 100 is both a one-percentage-point absolute increase and a doubling in relative terms. Choosing only the relative description can exaggerate the practical impression. Give the reader enough context to understand both magnitude and uncertainty.

Write benefits and harms in fair balance

Use parallel prominence, detail, time horizon, and numerical framing. Do not describe benefit vividly and risk vaguely, or put limitations where readers are unlikely to see them. Separate what happened in the study population from what may happen to an individual.

Terms such as common, rare, serious, mild, positive, and significant can carry technical and everyday meanings. Explain the intended meaning and, when possible, accompany frequency labels with numbers.

Readability formulas are screens, not verdicts

Readability formulas usually respond to visible features such as sentence length and word length. They can flag dense text and help compare drafts, but they do not measure scientific accuracy, organization, visual usability, cultural appropriateness, emotional response, or actual comprehension. A low score can be gamed by replacing precise terms or chopping logic into fragments.

Use a formula as one diagnostic. Then review vocabulary, concepts, navigation, actionability, numbers, visuals, tone, and intended-user performance.

Design carries meaning

Typography, spacing, line length, contrast, hierarchy, white space, and responsive behavior affect whether content can be used. Headings and summaries should expose the route through the information. Tables need plain labels and should not force mobile readers to compare distant columns. Icons require labels when their meaning is not universal.

Accessibility includes more than visual design. Plan for semantic headings, keyboard navigation, meaningful link text, text alternatives for informative images, captions or transcripts for media, sufficient contrast, scalable text, and information that does not depend on color alone when the eventual web implementation is built. These details must be checked in the implemented page, not assumed from the Markdown.

Visuals must clarify the evidence

Choose a visual for a defined reader question. Use human-scale denominators and comparable icons when showing frequencies. Use timelines for study flow or treatment steps. Label axes, groups, time, units, and uncertainty. Do not use decorative area, truncated axes, emotionally loaded imagery, or unequal icon arrays to dramatize an effect.

Test whether the intended audience interprets the visual correctly without the writer explaining it. A beautiful graphic that generates the wrong conclusion is a writing defect.

User testing closes the loop

Ask intended users to find and explain critical information and describe what they would do. Observe navigation and hesitation. Do not ask only whether they “like” the document. Test high-risk content such as dosing, consent choices, symptoms requiring action, benefit-risk comparisons, withdrawal, contact routes, and the distinction between group evidence and individual care.

Revise and retest. Document the audience, tasks, findings, changes, and unresolved limitations. Expert review and readability scoring cannot substitute for intended-user evidence.

Plain-language QC card

Check:

• audience and decision are explicit;
• essential information appears early and is easy to find;
• technical concepts are explained without changing meaning;
• benefit, harm, limitation, and uncertainty receive fair balance;
• numbers use consistent denominators, populations, and time frames;
• every action states who should do what, when, and how;
• headings, lists, tables, links, and visuals support navigation;
• tone is respectful and avoids blame, stigma, false reassurance, or alarm;
• general information is not framed as individual medical advice;
• intended users have tested the high-risk content where the project permits.