Longer The Sentence, Greater The Strain

By Nirmaldasan


—  This article appeared in the October-December 2011 issue of Vidura, a quarterly journal of the Press Institute of India: http://pressinstitute.in/archvd2011/oct-dec-vidura-11.pdf —

All plain English experts echo Robert Gunning’s advice: “Keep sentences short.” The longer the sentence, the greater the strain on the reader. Harold Evans, author of Newsman’s English, writes: “The real seduction of the simple sentence is that taken by itself, it is short and it is confined to one idea. The real trouble with so many compound-complex sentences is that they have to carry too many ideas.”

Martin Cutts, in the Oxford Guide To Plain English, has this to say: “More people fear snakes than full stops, so they recoil when a long sentence comes hissing across the page.” He recommends an average sentence length of 15-20 words.

Jyoti Sanyal, author of Indlish (the book for every English-speaking Indian) writes: “Based on several studies, press associations in the USA have laid down a readability table. Their survey shows readers find sentences of 8 words or less very easy to read; 11 words, easy; 14 words fairly easy; 17 words standard; 21 words fairly difficult; 25 words difficult and 29 words or more, very difficult.” We will return to this readability table a little later.

Rudolph Flesch, creator of the Flesch Reading Ease formula, studied the readability of various magazines: Scientific (very difficult), Academic (difficult), Quality (fairly difficult), Digests (standard), Slick-fiction (fairly easy), Pulp-fiction (easy) and Comics (very easy). He counted the number of syllables per 100 words and measured the average sentence length in words. He put these two variables into a complex formula in an article titled ‘A New Readability Yardstick’, published in the 3 June 1948 issue of the Journal of Applied Psychology.

Now words may be monosyllables (short), disyllables (medium) or polysyllables (long). So an average sentence comprising 17 long words may still be a strain on the reader. In early 2005, when I was a senior sub-editor with The Hindu, I realized that the best way to overcome this problem was to measure the sentence in syllables.

While it is easy to count words, counting syllables may not be all that easy. But with a little practice, anyone can count syllables swiftly. Remember that it is the syllable that determines the rhythm of prose. The syllable is the basic unit of utterance. Each syllable has only one vowel sound. ‘Television’ has four syllables; ‘Internet’ has three; ‘Radio’ has two; and ‘Print’ has only one!

Flesch writes: “If in doubt about syllabication rules, use a good dictionary. Count the number of syllables in symbols and figures according to the way they are normally read aloud, e.g. two for $ (‘dollars’) and four for 1918 (‘nineteen-eighteen’).”

The readability table, which we have already seen, may be better expressed in terms of syllables. Sentences of 10 syllables or less are very easy to read; 14 syllables, easy; 19 syllables, fairly easy; 25 syllables, standard; 33 syllables, fairly difficult; 42 syllables, difficult; and 56 syllables or more, very difficult.


Average sentence length (words)

Average sentence length (syllables)


of style


29 or more

56 or more

Very difficult








Fairly difficult








Fairly Easy






8 or less

10 or less

Very easy

But this table, derived from a simplification of Flesch’s observation of a pattern of ‘Reading Ease’ scores, does not identify the level of the readers for whom a text may be easy or difficult.

So here follows a formula that measures the readability of a text on a scale of 1 to 17+ years of schooling. The Strain Index, which I evolved as an alternative to Gunning’s Fog Index, is a syllable-counting formula. Unlike many a readability formula which intimidates the user with a complex equation, the Strain Index is very easy to use. The plain English expert William DuBay called it ‘remarkably simple’.

In its popular form, Strain Index = S3 /10 (S3 is the number of syllables in three sentences). Let us take an example:

‘I just don’t agree with this hoo-ha about short sentences and simple words,’ said PM. ‘If I can write long sentences well, why shouldn’t I?’ Nor does PM agree with the advice on the use of everyday words.

That passage comes from an article titled ‘Shrink Or Sink’ in Sanyal’s Indlish. The sample has 53 syllables. So, Strain Index = 53 / 10 = 5.3 years of schooling; a Standard V student can understand what Sanyal has written.

But to get a better estimate of the readability of a text, one must test more three-sentence samples or choose a long sample. In its non-popular form, Strain Index = S30 / 100 (S30 is the number of syllables in 30 sentences). This is the same as taking 10 three-sentence samples and calculating the average.

It is possible, though not necessary, to apply the formula to a full text consisting of ‘n’ sentences. In this case, the general form of the Strain Index = 0.3 x (Sn / n), in which Sn is the number of syllables in ‘n’ sentences. But always remember that any readability formula should only be applied on well-written texts.


One Response to “Longer The Sentence, Greater The Strain”

  1. How To Write An Article For Inspiring Interns (Or Any Other Blog) « Inspiring Interns Blog Says:

    […] really hard to read, long and repetitive sentences leave more room for error. Research shows that 11 words is the optimum length for a readable sentence, and 25 the absolute […]

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