Health-literacy standards
Spanish readability measures: measure Spanish as Spanish
English formulas misread Spanish, where words are longer on average. Spanish has its own measures: Fernández-Huerta, the Szigriszt-Pazos perspicuity index with the INFLESZ scale, and SOL.
Owner: Content lead and the Spanish-language reviewer · Checked against its sources on
In 30 seconds
- English formulas rate clear Spanish as harder than it is, because Spanish words have more syllables on average.
- Use Spanish measures: Fernández-Huerta, the Szigriszt-Pazos index read on the INFLESZ scale, and SOL.
- SOL reports a grade, so a Spanish document can be compared with its English source.
Why English formulas don’t fit
English formulas count syllables per word. Spanish words have more syllables on average, so an English formula rates clear Spanish text as harder than it is. A translated document can look like it missed its grade when it didn’t.
Synthetic example
The same plain instruction in English and Spanish. Each dot is one syllable.
English
Take one pill each morning with your breakfast.
8 words · 10 syllables · 1.25 syllables per word
Spanish
Tome una pastilla cada mañana con el desayuno.
8 words · 18 syllables · 2.25 syllables per word
Fernández-Huerta
A 1959 adaptation of Flesch Reading Ease for Spanish, with a seven-band interpretation scale. It is the earliest and still widely cited Spanish measure.
Szigriszt-Pazos and the INFLESZ scale
The Szigriszt-Pazos perspicuity index is a later Spanish adaptation of Flesch. The INFLESZ scale, validated on Spanish texts, reads its score in five bands.
- Very difficult: below 40
- Somewhat difficult: 40 to 55
- Normal: 55 to 65
- Fairly easy: 65 to 80
- Very easy: above 80
The INFLESZ scale, 0 to 100Higher is easier
Language-access self-audit: 12 questions, 10 minutes
SOL
SOL adapts SMOG to Spanish and reports a grade, so a Spanish document can be compared with its English source on the same kind of scale.
How HealthLiteracyCopilot uses them
HealthLiteracyCopilot measures Spanish with SOL, Fernández-Huerta and INFLESZ, not English formulas, and sets a target per document type.
Your next step
Paste a public notice. See its reading level by three instruments, the gap to your target and up to three passages to fix first. No account.
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Sources
- Barrio-Cantalejo IM et al. Validación de la Escala INFLESZ para evaluar la legibilidad de los textos dirigidos a pacientes. Anales del Sistema Sanitario de Navarra, 31(2), 2008
- Fernández Huerta J. Medidas sencillas de lecturabilidad. Consigna, 214, 29–32, 1959
- Contreras A et al. The SOL formulas for converting SMOG readability scores between health education materials written in Spanish, English, and French. Journal of Health Communication, 4(1), 1999
Questions
Can we run Flesch–Kincaid on Spanish text?
You can, but the grade will be too high. Use a Spanish measure.
Which Spanish variants do you support?
U.S., Puerto Rico, Mexico or Spain Spanish, with usted or tú.