Table 1. Readability assessment tests for influenza patient education materials.
SMOG: Simple Measure of Gobbledygook; IELTS: International English Language Testing System; CEFR: Common European Framework of Reference for Languages; UCSF: University of California San Francisco; CDC: Centers for Disease Control and Prevention; AOA: American Osteopathic Association
| Source | Flesch Reading Ease | Flesch Kincaid Grade Level | Gunning Fog Index | SMOG Index | Automated Readability Index | Spache Formula | Dale-Chall Formula | Powers-Sumner-Kearl | Raygor Readability Graph | Cole-man Liau Index | Fry Readability Graph | IELTS | CEFR | Lix and Rix Readability Formulas | Lensear Write Readability Formula | FORCAST Readability Formula |
| UpToDate (Symptoms and Treatment) | 51.25 | 11.53 | 14.72 | 13.19 | 13.08 | 5.5 | 9.5 | 8.5 | 10.5 | 11.5 | 10.5 | 7.0 | B2/C1 | 55, 6.5 | 11 | 11.5 |
| UCSF | 57.48 | 9.61 | 12.91 | 12.31 | 10.47 | 4.8 | 9.7 | 8.4 | 10.6 | 11.36 | 9.8 | 6.8 | B2.2 | 50.3, 5.8 | 9.6 | 10.7 |
| UpToDate (Prevention) | 50.5 | 9.72 | 13.32 | 12.53 | 11.06 | 5.2 | 10.1 | 8.6 | 10.8 | 13.85 | 10.2 | 7.0 | B2.3 | 52.1, 6.1 | 10 | 11 |
| CDC | 78.98 | 5.585 | 8.56 | 8.84 | 6.07 | 4.9 | 5.9 | 6.2 | 6.4 | 7.43 | 5.7 | 5.5 | B1 | 35.2, 4.1 | 5.8 | 6.0 |
| AOA | 42.6 | 12.35 | 15.65 | 14.3 | 13.1 | 5.4 | 10.2 | 8.7 | 11 | 13.21 | 10.4 | 7.1 | B2.4 | 53.2, 6.2 | 10.1 | 11.2 |
| My Health Alberta | 73.91 | 6.01 | 8.4 | 9.04 | 6.78 | 4.6 | 5.8 | 6.5 | 7.2 | 9.33 | 6.7 | 5.6 | B1.1 | 40.5, 4.6 | 6.2 | 7.0 |
| American Thoracic Society | 61.81 | 8.33 | 11.56 | 11.38 | 9.05 | 5.3 | 6.1 | 7 | 8.5 | 10.97 | 7.8 | 6.2 | B2 | 46.3, 5 | 7.5 | 8.3 |
| KidsHealth | 72.4 | 6.7 | 8.6 | 9.2 | 7.3 | 4.6 | 5.9 | 6.2 | 7.8 | 10.4 | 6.4 | 5.7 | B1.3 | 38,7, 4.4 | 6.5 | 7.1 |
| CDC (Prevention) | 70.3 | 6.8 | 8.5 | 8.9 | 7.2 | 4.7 | 6.3 | 6.9 | 7.4 | 9.6 | 7.1 | 5.8 | B1.4 | 41.2, 4.5 | 6.9 | 7.3 |
| Families Fighting Flu | 68.7 | 6.5 | 8.9 | 9.3 | 7.4 | 4.8 | 6.4 | 7.1 | 7.5 | 10.6 | 7.2 | 6.0 | B1.5 | 42.3, 4.6 | 7.0 | 7.4 |
| UC Davis Health | 64.8 | 7.6 | 9.7 | 10.2 | 8.3 | 5.2 | 6.7 | 7.4 | 8.1 | 11.1 | 7.9 | 6.1 | B2.1 | 43.6, 4.9 | 7.8 | 8.2 |
| Elsevier | 63.2 | 8.1 | 10.4 | 10.7 | 8.6 | 5.6 | 7.1 | 7.9 | 8.5 | 11.3 | 8.2 | 6.3 | B2.2 | 45.1, 5.2 | 8.0 | 8.8 |
| U.S. Pharmacist | 61.7 | 8.9 | 11.3 | 11.6 | 9.2 | 5.9 | 7.8 | 8.4 | 9.0 | 12.5 | 8.7 | 6.5 | B2.4 | 47.8, 5.7 | 9.1 | 9.4 |
| Mayo Clinic | 62.9 | 8.3 | 10.8 | 11.1 | 8.9 | 5.7 | 7.3 | 8.0 | 8.7 | 11.6 | 8.4 | 6.4 | B2.3 | 46.8, 5.3 | 8.2 | 9.1 |
| UC Davis Health (Parents of Children) | 62.4 | 8.3 | 10.5 | 10.8 | 8.7 | 5.7 | 7.2 | 8.0 | 8.6 | 11.4 | 8.3 | 6.4 | B2.3 | 46.2, 5.3 | 8.1 | 8.9 |
| UCSF Health (Staying Healthy) | 79.3 | 5.6 | 7.2 | 7.8 | 6.3 | 4.4 | 5.9 | 6.5 | 6.8 | 8.9 | 6.3 | 5.6 | B1.2 | 38.7, 3.9 | 5.8 | 6.2 |
| Allegheny Health Network | 65.2 | 7.9 | 9.6 | 9.9 | 8.4 | 5.3 | 6.8 | 7.7 | 8.2 | 10.7 | 7.9 | 6.2 | B2.1 | 44.9, 5.0 | 7.6 | 8.5 |
| UCSF: Benioff Children’s Hospitals | 63.7 | 8.2 | 10.6 | 10.9 | 8.8 | 5.8 | 7.3 | 8.1 | 8.7 | 11.5 | 8.4 | 6.5 | B2.4 | 47.0, 5.4 | 8.2 | 9.0 |