I have taken several indexing courses and every instructor had her own way of explaining how an indexer determines what information should be included in an index. One said, “make sure that you don’t index passing mentions or name dropping.” Another said, “every index entry should take the reader to helpful information.” But what is helpful? And is that one sentence a passing mention? 

Recently, I attended an indexing webinar, hosted by Editors Canada. The presenter explained that he uses the happy test to determine if something should be included in the index. If the reader follows the index entry to the page in the book, will they be happy with the information they find there? 

And that, my friends, made more sense to me than any other explanation I had been given so far. Because we all know that unhappy feeling of looking up a word in an index, flipping to the page in the book, and finding that word…but not much else. Not helpful. Not happy. 

Now I focus on creating helpful indexes, and happy readers.