What is a typical rate for a textbook contributor?

Q: What is a typical rate for a textbook contributor? Do I have any negotiation power if I think the rate isn’t fair?

A: Lorraine Papazian-Boyce, author of ICD-10-CM/PCS Coding: A Map for Success, and the upcoming Pearson’s Comprehensive Medical Coding: ICD-10-CM/PCS, ICD-9-CM, CPT, HCPCS:

“I’ve contributed to dozens of projects for multiple publishers over the last 8-9 years. It is a wonderful way to get started in the field, gain credibility with a publisher, and earn $ here and now. The rate for contributors depends on the type of content you’re being asked to develop, such as exercises, a chapter, supplements, etc. It also varies by field and publisher.