Couldn't pass this one up. From CNN concerning Ben Bernanke's financial disclosures:
Bernanke was paid $162,100 to be a Fed governor in 2004, and took a slight pay cut to become the chairman of the White House's Council of Economic Advisors earlier this year. He received royalties on one textbook from Pearson worth between $50,001 and $100,000 in 2004, and royalties on a another textbook from McGraw Hill worth only between $201 and $1,000. As of 2005 the Fed chairman is paid $180,100.
For those keeping score, his principles text with Robert Frank is the McGraw Hill book and his intermediate text with Andrew Abel is the Pearson book.
Take care not to generalize too much, as it is just a sample size of one author who happens to have two books. We also don't know the full terms of his contract (if he received an advance from the publisher, and if so, how much). Gregory Mankiw is another macroeconomist with both a principles and an intermediate book (and both are strong sellers). Not sure if he had to disclose his finances when he was on the CEA. (Bernanke is currently on the CEA, but it wasn't until now that the media reported on his finances.) David Colander also has written books for principles and intermediate macro.
Does producing a textbook at another level in the same field lower the average cost of production (writing)? (That is, are there economies of scope?) Does it depend on the field? (Probably.) Not having done it yet, I couldn't tell you from experience, but it's an interesting question.
The comparison of Bernanke's and Greenspan's finances in the article is interesting too.
Another difference might be that the intermediate book was in the first year of that edition's cycle, while the principles book might have been in the second or third year. In fact, that's likely, given the time needed to make revisions--one wouldn't want two simultaneous deadlines.
That's possible. That would almost certainly make a difference in new book sales for that year. The intermediate book is copyright 2005 (5th ed) and the principles book 2004 (2nd ed).