Terms weren't disclosed.
New York-based McGraw-Hill is a leading producer of textbooks, the publisher of BusinessWeek magazine, and the parent of credit-rating service Standard & Poor's (search). It said the businesses of the two groups have a lot of similarities but no overlaps.
Closely held J.D. Power of Westlake Village, Calif., provides independent marketing data about several industries beside the automotive market, including finance and insurance, health care and energy.
The transaction is expected to close in April.
The firm, founded by J.D. Power III in 1968, awards badges of excellence in dozens of categories based on yearly customer satisfaction surveys.
Its studies are independently financed and then sold to automakers as a marketing tool.
Only top-rated performers are allowed to license the use of their awards in advertising.
Shares of McGraw-Hill slipped 50 cents, or 0.5 percent, to $95.41 on the New York Stock Exchange (search).