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Answer: The CDC Clear Communication Index is a 20-item, research-based checklist for developing and assessing public materials. Each item scores zero or one; the total converts to a scale of 100, and 90 or higher is passing.

The seven areas

Main message and call to action, language, information design, state of the science, behavioral recommendations, numbers, and risk.

The behavioral recommendations, numbers, and risk items may not apply to all materials. The estimated time to complete the Index is 15 minutes.

Uses

• Inform the design of a new product, or assess clarity before public release.
• Foster discussion between writers and reviewers.

Limits

• The Index cannot take the place of formative research or pretesting with your intended audience.
• Without a budget for formal testing, improvise: ask individuals who most closely resemble your readers to read your draft and listen to their reactions.
• Also ask readers with some distance from the project; a fresh pair of eyes often catches the obvious problems.

See also

• plain-readability-formulas-limits
• plain-language-test-with-readers

Claims

• id: C1 claim: Each item scores zero or one; 90 or higher passes. source: S1 evidence: "Although 100 is an ideal score, 90 or higher is passing."

• id: C2 claim: The Index has 20 items. source: S1 evidence: "The Index contains 20 items, each with a numerical score of zero or one."

• id: C3 claim: The Index does not replace pretesting. source: S1 evidence: "It cannot take the place of formative research or pretesting with your intended audience."

• id: C4 claim: Fresh readers catch obvious problems. source: S2 evidence: "A fresh pair of eyes often picks up the \"obvious\" problems"

Sources

• [S1] CDC Clear Communication Index: User Guide. Centers for Disease Control and Prevention (CDC). https://www.cdc.gov/ccindex/pdf/clear-communication-user-guide.pdf . License: US government work, public domain. Accessed 2026-11-09.

• [S2] A Plain English Handbook. U.S. Securities and Exchange Commission. https://www.sec.gov/pdf/handbook.pdf . License: US government work, public domain. Accessed 2026-11-09.

License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted). Sources: US federal government works (GSA, GPO, SEC, CDC), public domain in the United States; third-party quotations inside those works were not used. Text was condensed and changed from the originals.

@misc{iil_note_mvmkj6z2,
  author = {{iinventedlight}},
  title = {{Score a draft with the Clear Communication Index, then still test it}},
  howpublished = {iinventedlight Library},
  year = {2026},
  date = {2026-11-09},
  url = {https://iinventedlight.com/library/notes/plain-score-with-clear-communication-index/},
  note = {Permanent ID iil:note:mvmkj6z2. License: CC-BY-4.0.},
}

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