Have you heard of the 5 finger rule?
I have taught this rule to my students in the past. To find a good fit book, one test is to choose a few different pages and read the page. For each work that you can't understand, you put up one finger. If you go past 5 on a page, the book is too difficult.
On the surface, this sounds like a great rule. Obviously, you don't want too many difficult words on a page. The question is, how many unknown words are too many?
I decided to apply the 5 finger rule to a book. It was difficult to do this in English, because it is my first language, I'm a college educated adult etc. So how was I going to apply this rule to my life? In Spanish.
I found a book that looked interesting to me. In English, it is called 10-10-10 A Life Transforming Idea. Before ordering the book, I tested a few pages to see how many words I did not understand. I averaged 5 words a page, with some pages having as few as 2 words, and others having up to 8 words. It would seem like this was a "good fit" book for me.
How well could I understand what I was reading? Well, I could understand most of what was happening on each page. I had to read a few sentences more than one time, but overall I was able to understand the book and its concepts.
How much effort did it take to read? There was a big difference between the pages with 2 unknown words, 5 and 8. At 2, I felt confident and like it was easy to read. Above 3, the page started to feel more challenging and take more effort. I have to remember, though, that I am highly motivated to read, have skills to deal with unknown words, and a strong foundation. The students who are having the most trouble with reading might have less tolerance for unknown words.
How many unknown words were in the book? Well, the book averaged 5 unknown words per page, and was over 250 pages. . . so there were more than 1,250 words in the book that I did not understand. If the book had been 100 pages, it would have been 500 words that I did not understand. There was not that much repetition. So . . . there were a ton of unknown words in this one book.
How many words was I able to determine the meaning by context? About 2-5%. Not that many. I could get the gist, from some sentences, but I would not say that I learned the meaning of the words just by reading and being exposed to an unknown word.
How many new words did I learn without any further studying? If I mean by learn that I would be able to use the word in a conversation after reading the word and figuring out the meaning by context, but not studying it - 0 words in the book.
This might be that I am a poor learner of words. I did learn quite a few of the words after I made flashcards and studied them. I needed to study each word on average 5 times before I felt comfortable using it in a conversation.
What are my new thoughts on the 5 finger rule? For readers that are low in confidence, having 1 unknown word a page is probably sufficient. The 5 finger rule makes for a frustrating reading experience. For readers with a higher level of confidence, about 2 words per page is probably the perfect challenge level.