Forget everything you may have read about coping with children's temper tantrums. Time-outs, sticker charts, television denial—for many, none of these measures will actually result in long-term behavior change, according to researchers at two academic institutions.

Instead, a set of techniques known as "parent management training" is proving so helpful to families struggling with a child's unmanageable behavior that clinicians in the U.S. and the U.K. are starting to adopt them.

Aimed...