LINGUIST List 22.2332 Thu Jun 02 2011 Disc: Error in the Fernandez Huerta Readability Formula Editor for this issue: Elyssa Winzeler <elyssalinguistlist.org> To post to LINGUIST, use our convenient web form at http://linguistlist.org/LL/posttolinguist.cfm. Directory         1.     Gwillim Law , Error in the Fernandez Huerta Readability Formula Message 1: Error in the Fernandez Huerta Readability Formula Date: 27-May-2011 From: Gwillim Law <glawmeasinc.com> Subject: Error in the Fernandez Huerta Readability Formula E-mail this message to a friend José Fernández Huerta published his formula for calculating the readability of text in Spanish in 1959. It is still widely used. I found six web pages that contain the actual formula, and many more where it is cited. I have two strong reasons for believing that the formula contains an error. I would be interested in getting additional feedback on the matter. Also, if there is a consensus that the formula does contain an error, where would I go to report it? The Huerta score* was an adaptation of the Flesch Reading Ease score into Spanish. The Flesch formula for English text, first published in 1948, is: Flesch = 206.835 - 84.6 * syllables/words - 1.015 * words/sentences Scores run roughly from 30 to 100, with higher scores being easier to read. This makes sense. Sentences with more words in them will produce a lower score; words with more syllables in them will produce a lower score. The Huerta formula is usually presented as 206.84 - (0.60 * P) - (1.02 * F), where P = number of syllables and F = number of sentences, as counted in a sample containing 100 words. Applying the same sanity check, we see that if the number of syllables per word increases, the score decreases, as expected; but if the number of sentences increases, the score also decreases. Now, if the number of sentences in a 100- word sample increases, each sentence must be getting shorter. That should make the readability of the passage increase, not decrease. (Reason 1.) In its original form, the Huerta formula is not scalable. To compare it to the Flesch formula, one would have to convert it to a formula that works for a passage containing any number of words. When I do that, I come up with the formula Huerta = 206.84 - 60 * syllables/words - 102 * sentences/words Note that if words = 100, this works out the same as the original Huerta formula. Note also that it matches the Flesch formula almost term for term. The coefficients of (syllables/words) in the two formulas differ by about 40%, but that's understandable, because the average number of syllables in a Spanish word is greater than the corresponding ratio in English. It's the last term that looks wrong. The coefficients are very different (1.015 and 102), but that's because I converted the Huerta formula to make it scalable. In its original form, the coefficient was 1.02. But the real difference is that the fraction is inverted. (Reason 2.) Since Fernández Huerta avowedly based his work on that of Flesch, it seems to me that the obvious conclusion is that he made a mistake. When he decided to stipulate a sample of 100 words, he got confused and didn't realize that he had inverted the fraction. Perhaps he tested his formula using a sample with 10 sentences, in which case the two formulas give the same result: 1.02 * 10 = 102 * 10 /100. Gwillim Law References: Original publication of the Huerta formula: Fernández Huerta, José. Medidas sencillas de lecturabilidad. Consigna 1959; (214): 29-32. Some web pages describing or using the Huerta formula: http://www.ideosity.com/SEO/SEO-Readability-Tests.aspx http://www.standards-schmandards.com/exhibits/rix/ http://www.utexas.edu/disability/ai/resource/readability/manual/huerta-calculate-English.html http://scielo.isciii.es/scielo.php?script=sci_arttext&pid=S1135-57272002000400007&lng=en&nrm=iso http://www.faculty.de.gcsu.edu/~cbader/5210/fryforeign.htm Linguistic Field(s): Applied Linguistics Read more issues|LINGUIST home page|Top of issue Page Updated: 02-Jun-2011       About LINGUIST    |   Contact Us       While the LINGUIST List makes every effort to ensure the linguistic relevance of sites listed on its pages, it cannot vouch for their contents.