Abstract
Difficulties and bonuses of evaluating injury prevention programmes are illustrated by reference to an evaluation of the New Zealand's Children's Nightclothes Act 1977. It is demonstrated that despite the difficulties encountered in that evaluation, and the equivocal results, there were significant bonuses which more than justified the resources devoted to the evaluation. The paper is presented in an attempt to encourage others to evaluate thermal injury countermeasures who may be hesitant to do so because of the difficulties they foresee.