From the would-be author who insists to his would-be editor that "my grandkids love this story" to the award committee member who says "my ten-year-old thought this book was boooorrrring," the children's book world is replete with those who use their own children as test subjects. Expanding the notion of "my kids" to those children with whom we have professional contact (as teachers or librarians) gives us an even bigger pool of lab rats even while the scientific validity of the test population remains questionable.
I'm all for writers, award committee members, reviewers, teachers, and librarians "trying out" books with kids, but I think we need to be watchful of what they tell us. My colleague Anne Quirk talks about the "Steve and Daphne Show" she witnessed one year at a Best Books for Young Adults committee, where, as dutifully supplied by a committee member, opinions from these two teens from a single high school library seemed to be providing the pivotal swing vote. I myself like to use the fact that the two-year-old from downstairs loves to scream "ROAR ROAR ROAR" as evidence that Bob Shea's Dinosaur Vs. Bedtime should win the Caldecott Medal.
But talk about experimenter effect! Zena Sutherland used to quote Ursula Nordstrom as saying that kids will enjoy the telephone book if it means they're getting their mother's attention, just as politicians know not to say that Harold Robbins is their favorite writer. Everybody wants to make somebody happy. And just because your kids like or don't like something doesn't mean that other kids will feel the same way. Proximity does not an expert witness make.