Development of SMOG-Cro Readability Formula for Healthcare Communication and Patient Education

Sanja Brangan


Effective communication shows a positive impact on patient satisfaction, compliance and medical outcomes, at the same time reducing the healthcare costs. Written information for patients needs to correspond to health literacy levels of the intended audiences. Readability formulas correlate well with the reading and comprehension tests but are considered an easier and quicker method to estimate a text difficulty. SMOG readability formula designed for English language needs to be modified if used for texts in other languages. The aim of this study was to develop a readability formula based on SMOG, that could be used to estimate text difficulty of written materials for patients in Croatian language. Contrastive analysis of English and Croatian language covering a corpus of almost 100,000 running words showed clear linguistic differences in the number of polysyllabic words. The new formula, named SMOG-Cro, is presented as an equation: SMOG-Cro =  2 + √4+ syllables, with the score showing the number of years of education a person needs to be able to understand a piece of writing. The presented methodology could help in the development of readability formulas for other languages. We hope the results of this study are soon put into practice for more effective healthcare communication and patient education, and for development of a health literacy assessment tool in Croatian language.


doctor-patient communication, patient education, readability formulas, SMOG, health literacy, patient-centred health care

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