Roberts' four studies tested whether the traditional spank back-up for timeout was necessary in the Forehand-McMahon (87) version of behavioral parent training and what alternatives could be used instead of spanking to enforce cooperation with the time-out chair in the clinic.
Roberts' series of randomized studies demonstrated causally conclusive evidence that this goal is achieved most effectively by the spank back-up and by the room-isolation back-up, both of which were significantly more effective than the restraint back-up or child-determined-release conditions.
This adjustment occurred for fifteen (42%) of thirty-six children, with three switching from the spank back-up to the room isolation, and the other twelve switching from one of the other three back-up tactics to the spank back-up.
Successful compliance was measured in Roberts' studies by compliance with parental commands or cooperation with time-out, situations in which the spank back-up never needed to be used.
The inconsistency of Gershoff's effect sizes from Roberts' studies is due to differences in what the spank back-up was compared with.
Finally, Gershoff quoted Day and Roberts as saying in 1983 that "there was no support for the necessity of the physical punishment," (109) which actually meant that the traditional spank back-up was no longer the only maximally effective back-up for time-out.
Roberts later improved the protocol by switching to either the spank back-up or the room-isolation back-up after seven escapes from time-out.
In sum, the only four causally definitive studies of spanking for defiant refusal to comply with other tactics have shown that a two-swat spank to the buttocks is tied with one other enforcement tactic as the most effective tactic in that situation with two- to six-year-olds.
But far from settling the score, the report, being published in the AMA's Archives of Pediatrics & Adolescent Medicine, is sure to fuel the already white-hot debate over whether to spank or not to spank.
They have never been able to answer the ``chicken or egg'' question - whether a child's bad behavior caused the parent to spank, or whether a parent's pattern of spanking promoted aggressive, bad behavior.
Of the children whose mothers didn't spank, two years later, their misbehavior score was better, they had less misbehavior,'' Straus said.