Archive for February, 2008

Information Density

February 27, 2008

By Nirmaldasan

(nirmaldasan@hotmail.com)

“Even short sentences can be too densely packed. The shortest possible statement may not be the easiest for readers to digest,” writes John Kirkman in his book ‘Good Style’. He suggests that ‘a densely packed statement needs to be loosened to make it easier for readers to absorb’. He presents three ‘densely packed’ sentences and two ‘eased out’ alternative versions for each. But it is interesting to note that the average sentence lengths of all but two ‘eased out’ versions are shorter than the ‘densely packed’ original sentences.

Let us look at just two of his examples. Here is his first example. “For a given material thermal resistivity (inverse conductivity) varies linearly with electrical resistivity when either the orientation or the crystallinity vary.” This contains one sentence, 21 words and 53 syllables. Its Strain Index is 15.9 (S3/10, where S3 is the number of syllables in three sentences).

Here is Alternative Version 1. “If either the orientation or the crystallinity of a material is changed, the thermal resistivity (inverse conductivity) and the electrical resistivity vary. The relationship between the resistivities is linear.” This contains two sentences, 29 words and 66 syllables. Its average sentence length is 14.5 words. Its Strain Index is 9.9.

Here is Alternative Version 2. “A change in the orientation or the crystallinity of a material changes its thermal resistivity (inverse conductivity) and its electrical resistivity. The relationship between the resistivities is linear.” This contains two sentences, 28 words and 64 syllables. Its average sentence length is 14 words. Its Strain Index is 9.6.

The average sentence length and the Strain Index clearly show that the ‘eased out’ versions are better than the ‘densely packed’ original. In fact, Alternative Version 2 is better than Alternative Version 1.     

Now for one more example. “An approximately linearly decreasing relationship of modulus of elasticity with increasing temperature resulted.” This contains one sentence, 13 words and 37 syllables. Its Strain Index is 11.1.

Here is Alternative Version 1. “The result was a decreasing relationship between modulus of elasticity with increasing temperature. The relationship was approximately linear.” This contains two sentences, 18 words and 44 syllables. Its average sentence length is 9 words. Its Strain Index is 6.6.

Here is Alternative Version 2. “This resulted in an approximately linear decreasing relationship between modulus of elasticity and increasing temperature.” This contains one sentence, 15 words and 39 syllables. Its Strain Index is 11.7.

The Strain Index tells us that the original and the Alternative Version 1 are better than Alternative Version 2. Though the Strain Index is right about Alternative Version 1, it is wrong about Alternative Version 2. Qualitatively, Alternative Version 2 is also better than the original though it contains more words and more syllables.