We ask readers after they have finished a book if they would recommend it. The four possible answers are:
- “I would definitely recommend it to a friend” (these are the “promoters”)
- “I would possible recommend it to a friend” (these are the “neutrals”)
- “I would probably not recommend it to a friend” (these are the “weak detractors”)
- “I would definitely not recommend it to a friend” (these are the “strong detractors”)
The recommendation factor is calculated by subtracting the percentage of weak and strong detractors form the percentage of promote. A book with positive recommendation factor has more promoters than detractors and the larger the majority, the larger the word of mouth potential. A title with an excess of 60% promoters is basically a book that has the potential to be a viral hit, while a percentage between 30% and 60% is still a very good result.
Books with high completion rates and high recommendation factor are the lead candidates for a strong marketing campaign.
A book with negative recommendation factor is a book with more detractors than promoters and that should be a warning sign. It means those who read the book, and we only include people who finished the book, disliked the book so much they would tell their friends not to read it.
There are special cases where a book can high a high completion rate but a low recommendation factor, usually 0-20%. These are what we call the “guilty pleasure” books. They deal with sex, erotica, horror or similar and are book that even engaged readers would not readily recommend to their “casual” friends. In such cases marketing is bets focused on influencer who through reviews can spread the word or on getting samples into the hands for many readers in the genre.
Books with low completion rates, but high recommendation factor are often niche titles that appeal to a particular demographic or niche, but not to the mass market. In such cases it is important to correctly position the audience to selectively read that particular audience. Word-of-mouth only works if it can spread in a community of like-minded souls. It will dissipate without effect if promoters are lost in an ocean of indifferent others.