The Science and Statistics Behind Spanking Suggests that

11-FULLER_FINAL_AFTERPROOF.DOC 2/17/2009 8:50 AM
2009] THE SCIENCE AND STATISTICS BEHIND SPANKING 287
For example, Dr. Straus often focuses on theoretical models and
surveys of adults that were spanked as teenagers. 221 While it is true that
spanking teenagers can be worse than mentally punishing them,
spanking young children almost never is. 222
Even on the rare occasion that Dr. Straus studied preteens, he only
focused on six- to nine-year-olds that were spanked an average of 156
times a year. 223 That’s up to thirteen times the normal rate. 224 Parents
who physically discipline rarely spank their nine-year-old more than
once a month. 225 With such an unnatural sample, it’s no wonder Dr.
Straus’ was able to associate corporal punishment with antisocial
behavior. 226 Many nine-year-olds that are spanked 156 times a year may
simply be more prone to behavior problems, regardless of the type of
punishment they get. 227
When researchers ignore preexisting conditions (like a child’s
preexisting misbehavior), they erroneously associate spanking with
harmful effects. 228 This is known as the “intervention selection bias.” 229
221. E.g., Straus, ROUNDTABLE, supra note 175, at 36-37 (mentioning his surveys of
teenagers, which found links to spousal assault and abusing one’s child later in life, then
generalizing such links to all spanking); STRAUS, supra note 33 (referring often to his theoretical
models and surveys of teenagers).
222. E.g., Larzelere, Review, supra note 17, at 827 (finding grounding less detrimental than
spanking for teens, but for young children, spanking was more beneficial than nine common
disciplines, including timeout and reasoning).
223. Rosellini, supra note 27 (“His research indicated that frequent spanking (three or more
times a week) of children 6 to 9 years old, tracked over a period of two years, increased a child’s
antisocial behavior, measured in activities like cheating, bullying, or lying.”);
ROBERT E. LARZELERE, CRITIQUE OF ANTI-SPANKING STUDY, available at
http://ches.okstate.edu/facultystaff/Larzelere/CritiqueStraus.html [hereinafter LARZELERE,
CRITIQUE] (“The only thing that Straus et al. (1997) have proven is that spanking 6- to 9-year-olds
at the rate of 156 times a year has a small, but detrimental effect (accounting for 1.3% of subsequent
variation in anti-social behavior). Most children spanked from 1 to 25 times annually were in their
most-improved group . . . .”).
224. See, e.g., Baumrind, Discipline Controversy, supra note 157, at 409 (saying that, by age
nine, only one-third of the parents spanked their children as often as once a month).
225. See, e.g., id.
226. See, e.g., supra note 223 and accompanying text.
227. See, e.g., Baumrind, Ordinary Physical Punishment, supra note 128, at 585 (“A child
who is not dispositionally compliant, however, is likely also to be less malleable and therefore likely
to require more forceful parental intervention . . . .”).
228. See, e.g., Robert E. Larzelere, Ph.D., Univ. Neb. Med. Ctr., The Difficulty of Making
Valid Causal Inferences from Passive Longitudinal Designs, Presentation at Univ. Cal., Berkeley on
Inferring Causality from Longitudinal Studies (Mar. 21, 2003), available at
http://ihd.berkeley.edu/larzelere.htm [hereinafter Larzelere, The Difficulty] (saying the intervention
selection bias is an explanation that, if ignored, can lead to incorrect conclusions about corrective
interventions. For instance, the association between mental health treatment and subsequent