Comparing Indexing Approaches: Diversity in Style and Content 
Indexers, like other freelancers, often work alone. Although they have unlimited access to indexes prepared by others via the bookstore or public library, they rarely have the opportunity to meet with other indexers to talk about indexing, indexing techniques, or a project they may be struggling with. This can be frustrating for both beginning and advanced indexers, especially those who receive little feedback from clients about the quality of their work.
Rowland, Marilyn. Editorial Freelancers Association (1995). Careers>Freelance>Indexing