A children’s classic that you can return to, even after growing up, is J.M. Barrie’s Peter Pan, first produced as a play in 1904 and then as a story book in 1911. The eponymous hero of Neverland who never grows up, the ferocious Captain Hook hunted by a ticking crocodile that has swallowed a clock, fairies, mermaids and ‘gay and innocent and heartless’ children who fly away to Neverland make Peter Pan an enjoyable reading experience.
No doubt a book for children, its grade level may be determined by a readability formula. Let us take 10 samples of three sentences each and apply the Strain Index (S3/10, where S3 is the number of syllables in three sentences). Since the book has 17 chapters, we may take one sample from the beginning and one from the end of each of the following chapters: I, V, IX, XIII and XVII.
Here are the scores for the 10 samples: 5.5, 7.9 (Chapter I); 6.0, 4.7 (Chapter V); 12.4, 14.6 (Chapter IX); 8.2, 5.9 (Chapter XIII); 6.2, 13.5 (Chapter XVII). Parts of the book are written at grade level 4 and parts at grade level 14. However, the average yields a Strain Index of 8.49. The mean deviation is 2.615 (sum of the deviations divided by the number of samples).
But why should the sample be restricted to three sentences? You may wish to take a longer sample. The general form of Strain Index = 0.3 * (Sn/n), where Sn is the number of syllables in ‘n’ sentences. I would recommend a sample of 30 sentences to simplify the calculation. Thus, for a longer sample, Strain Index = S30/100, where S30 is the number of syllables in 30 sentences.
Now in the 10 samples that we have taken, there are a total of 30 sentences and 849 syllables. Therefore, Strain Index = S30/100 = 849/100 = 8.49. Peter Pan is suited for students of Grade 8.