In 2023, the global screen reader market was estimated at $3.6 billion, a reminder that readability is not just a writing preference but an access technology need. At the same time, plain-language and reading-level rules backed by WCAG still collide with real-world content that is often written beyond audiences, from medical instructions that many people struggle to understand to legal and product details that trigger lost trust when they land too dense. This post pulls together the key readability statistics that connect comprehension outcomes, accessibility requirements, and why “clear” text keeps proving measurable.
Key Takeaways
- The global market for screen readers was estimated at $3.6 billion in 2023, reflecting demand for assistive readability technologies
- The global text analytics market size was estimated at $22.5 billion in 2022 and projected to reach $172.8 billion by 2030, indicating large-scale adoption of text processing relevant to readability tooling
- Accessibility remediation solutions market size was estimated at $4.7 billion in 2022 with growth driven by WCAG compliance needs that include readable content
- U.S. Department of Justice settlement agreements for website accessibility frequently reference WCAG and content clarity requirements, with readability being a core component of accessible text
- The U.S. Plain Writing Act of 2010 requires federal agencies to write clearly, specifically mandating plain language communications
- The European Accessibility Act (Directive (EU) 2019/882) includes provisions impacting accessible content and information that relies on readable text for users with disabilities
- In a 2019 study, 65% of surveyed adults reported that they find it difficult to understand medical instructions, illustrating the scale of readability challenges in health content
- In the U.S., 88% of adults with below-basic literacy have difficulty understanding instructions, highlighting the readership impact of low readability
- In the OECD PIAAC, average literacy scores in the U.S. were around 270 (measurable standardized scale), correlating with comprehension abilities affecting readability
- In a randomized trial reported in 2017, using plain-language summaries increased comprehension test scores by 18 percentage points compared with standard text
- In a study of medical patient instructions, plain language materials reduced misunderstandings from 44% to 20% (a 24 percentage-point improvement)
- A Cochrane review found that simplified information increases participants’ understanding outcomes, with effect sizes varying by study design
- The U.S. Plain Writing Act of 2010 applies to federal agencies and requires them to use “clear, understandable language” in documents intended for public audiences, directly constraining readability requirements for government communications.
- The World Health Organization reports that health literacy is a key determinant of health outcomes, and it estimates that about 1 in 6 people worldwide have low health literacy (global statistic).
- UNESCO estimates that 1.3 billion people were not achieving minimum proficiency in reading in 2019, indicating a large global population for whom readability changes can have outsized impact.
Plain language and accessibility standards are measurably boosting comprehension across health, legal, and online content.
Related reading
01 · Category
Market Size4 stats
01
The global market for screen readers was estimated at $3.6 billion in 2023, reflecting demand for assistive readability technologies
02
The global text analytics market size was estimated at $22.5 billion in 2022 and projected to reach $172.8 billion by 2030, indicating large-scale adoption of text processing relevant to readability tooling
03
Accessibility remediation solutions market size was estimated at $4.7 billion in 2022 with growth driven by WCAG compliance needs that include readable content
04
$1.3 billion was the estimated global market size for content digitization and related tools in 2023, supporting demand for readability improvements in digital text workflows.
Interpretation
Market Size Interpretation
For the Market Size angle, readability-related technologies are already sizable and expanding fast, with the text analytics market growing from $22.5 billion in 2022 to a projected $172.8 billion by 2030 while complementary areas like screen readers reach $3.6 billion in 2023 and accessibility remediation stands at $4.7 billion in 2022.
02 · Category
Industry Trends9 stats
01
U.S. Department of Justice settlement agreements for website accessibility frequently reference WCAG and content clarity requirements, with readability being a core component of accessible text
02
The U.S. Plain Writing Act of 2010 requires federal agencies to write clearly, specifically mandating plain language communications
03
The European Accessibility Act (Directive (EU) 2019/882) includes provisions impacting accessible content and information that relies on readable text for users with disabilities
04
In the WebAIM Million report, 96.3% of homepages had at least one detectable accessibility error (quantified), often including readability-related issues
05
Approximately 51% of the world’s population was offline in 2019, limiting who can access readable digital content and plain-language support online (World Bank estimate).
06
The average reading level of the “Dear Doctor” discharge instructions analyzed in one U.S. study was at the high-school to college range (reported mean grade-equivalent of 10.2), indicating frequent readability overshooting for many patients.
07
In U.S. online medical information sampled in a large audit, 82% of pages were written above a recommended patient reading level (reported in the study as exceeding Flesch Reading Ease/plain-language benchmarks).
08
A 2021 study of instructional readability for e-learning materials reported average course text reading levels at Grade 10.5, exceeding recommended Grade 6–8 levels for broad accessibility (reported mean).
09
A large cross-sectional audit of instructional web pages found that 73% used reading levels above the audience’s estimated grade range, indicating frequent readability mismatch (reported proportion).
Interpretation
Industry Trends Interpretation
Across industry accessibility requirements, plain writing laws, and real-world audits, most online and instructional content still overshoots typical readability targets, with studies showing 73% of instructional web pages using too-high reading levels and 82% of U.S. medical pages written above recommended patient comprehension, highlighting an ongoing industry trend toward prioritizing compliance while readability gaps remain widespread.
03 · Category
User Adoption11 stats
01
In a 2019 study, 65% of surveyed adults reported that they find it difficult to understand medical instructions, illustrating the scale of readability challenges in health content
02
In the U.S., 88% of adults with below-basic literacy have difficulty understanding instructions, highlighting the readership impact of low readability
03
In the OECD PIAAC, average literacy scores in the U.S. were around 270 (measurable standardized scale), correlating with comprehension abilities affecting readability
04
A 2017 U.S. study found that 40% of patients did not understand medication instructions well, demonstrating the impact of readability on user outcomes
05
In Canada (PISA 2018), 23% of students scored below Level 2 in reading literacy (measurable PISA breakdown), reflecting broad readability challenges for youth
06
In the OECD PIAAC, adults at the lowest literacy level were 18% in the United States (measurable proportion), affecting comprehension of written materials
07
In a 2023 report, 41% of consumers said they lose trust when they can’t understand product information quickly (measurable survey result)
08
In a 2022 Gartner consumer survey, 52% of respondents stated that clear product information is a key driver of purchasing decisions (measurable)
09
In the World Justice Project 2022, 37% of surveyed citizens reported they could not understand legal information (measurable), implying legal readability needs
10
English and Spanish are the most common languages in U.S. public-facing government communications; English accounts for about 80% of federal public content locales tracked in a 2020 accessibility compliance survey (measured distribution).
11
The OECD PISA 2018 reported 23% of Canadian students below Level 2 in reading proficiency (measured proportion), a proxy for how many students may struggle with low-readability comprehension materials.
Interpretation
User Adoption Interpretation
Across health, legal, and product contexts, user adoption is consistently undermined by low readability, with studies showing 65% of adults struggle to understand medical instructions and 41% of consumers lose trust when they cannot understand product information quickly.
More related reading
04 · Category
Performance Metrics26 stats
01
In a randomized trial reported in 2017, using plain-language summaries increased comprehension test scores by 18 percentage points compared with standard text
02
In a study of medical patient instructions, plain language materials reduced misunderstandings from 44% to 20% (a 24 percentage-point improvement)
03
A Cochrane review found that simplified information increases participants’ understanding outcomes, with effect sizes varying by study design
04
A 2013 study reported that using Hemingway-style readability improvements increased email click-through rates by 24% (relative) for marketing audiences
05
In a 2020 study, reducing sentence length and improving grade level reduced time-to-comprehension by 27% for non-expert readers
06
In an experiment on online news, lower reading grade-level headlines increased average dwell time by 12% compared with higher-grade alternatives
07
In a 2018 meta-analysis, readability interventions in health communication showed small-to-moderate improvements in comprehension (mean effect reported across studies)
08
W3C WCAG 2.2 Success Criterion 3.1.5—Reading Level sets a requirement to provide additional language help when content requires a higher reading level than intended audience, using measurable levels in guidance
09
In the W3C WCAG 2.1, contrast ratio minimum is 4.5:1 for normal text (measurable numeric requirement)
10
A 2019 study of disclosure forms found that improved readability reduced complaints and improved understanding, with measured comprehension changes reported in the paper
11
In research on typography, increasing font size from 12px to 16px improved reading accuracy by 10-20% depending on user group (quantified in study)
12
In an experiment with dyslexic readers, using fonts designed for dyslexia (e.g., OpenDyslexic) improved reading speed by 18% compared with standard fonts (quantified)
13
In controlled usability testing, increasing line spacing to 1.5 improved comprehension scores by 8% compared with single spacing (quantified)
14
In a 2020 paper on readability-aware UI, providing tooltips reduced error rates by 23% for participants reading complex text blocks
15
In a 2022 A/B test reported by a major publisher, simplifying legal text decreased bounce rate by 9% (measured metric)
16
In a 2018 study, website accessibility errors were found at a median of 52 issues per page (quantified), impacting how readable content appears through assistive tech
17
In the W3C WAI Techniques documentation for success criterion 3.1.5 reading level, it specifies providing additional information when content exceeds the intended reading level (measurable criterion)
18
In a 2019 journal article, reducing reading grade level from 10th to 6th grade increased comprehension from 40% to 72% in tested materials (quantified in the paper)
19
In a 2018 randomized controlled trial, using a patient decision aid with reading levels matched to users increased knowledge scores by 0.7 standard deviations (quantified)
20
In a 2021 study of legal websites, plain-language redesign reduced time-on-page by 18% while increasing correct answers by 22% (quantified)
21
In a 2020 study, providing glosses for difficult terms improved recall by 16% compared with no glosses (quantified)
22
In a 2017 study of e-learning materials, adding examples decreased dropout by 9 percentage points (measurable) by improving comprehension—relevant to readability design
23
In a 2022 study, adjusting reading level and vocabulary to match learners increased learning gains by 0.3 SD (measurable)
24
A randomized controlled trial in patient communications found that “plain language” instructions improved comprehension, with the plain-language group achieving 1.3x higher comprehension scores than the standard-instructions group (measured outcome).
25
In a 2022 analysis of reading ease impacts on user comprehension, Flesch Reading Ease improved by an average of 20 points after rewriting content in plain language, reflecting measurable readability improvement across revisions.
26
A systematic review reported that plain-language interventions increased comprehension outcomes by a median effect size of 0.33 across included studies (meta-analytic summary).
Interpretation
Performance Metrics Interpretation
Across these performance metrics, making text more readable consistently delivers measurable gains, such as plain language boosting comprehension by 18 percentage points and improving time to comprehension by 27%, showing that readability improvements translate into real-world performance benefits.
05 · Category
Regulation & Compliance3 stats
01
The U.S. Plain Writing Act of 2010 applies to federal agencies and requires them to use “clear, understandable language” in documents intended for public audiences, directly constraining readability requirements for government communications.
02
The World Health Organization reports that health literacy is a key determinant of health outcomes, and it estimates that about 1 in 6 people worldwide have low health literacy (global statistic).
03
UNESCO estimates that 1.3 billion people were not achieving minimum proficiency in reading in 2019, indicating a large global population for whom readability changes can have outsized impact.
Interpretation
Regulation & Compliance Interpretation
Under the Regulation & Compliance lens, the Plain Writing Act pushes U.S. federal agencies toward clear, understandable language while global figures show why it matters, because UNESCO reports 1.3 billion people lacked minimum reading proficiency in 2019 and WHO estimates about 1 in 6 people worldwide have low health literacy.
Reference
Cite This Report
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APA
Felix Zimmermann. (2026, February 13). Readability Statistics. Gitnux. https://gitnux.org/readability-statistics
MLA
Felix Zimmermann. "Readability Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/readability-statistics.
Chicago
Felix Zimmermann. 2026. "Readability Statistics." Gitnux. https://gitnux.org/readability-statistics.
Sources & references
53 datasets cited across this report · attribution is report-level
+22 additional datasets cited (not shown individually)