"It's a strikingly big phenomenon. Parenting style matters and it matters a heck of a lot," says Canada's chief statistician, Dr Ivan Fellegi, who oversaw the National Longitudinal Survey of Children and Youth carried out between 1996 and 1997.
The survey of families of 23,000 children under 11, divided parenting styles into four types from "positive interaction" (in which parents laughed and played games with children) through to "hostile interaction" (in which parents punish children frequently, tell them they are bad and express anger often).
Dr Mike Sheridan, director general of Household Surveys for Statistics Canada, says less than 10 per cent of children with positive parents had behaviour difficulties while eight out of 10 children whose parents used negative approaches had problems.
The study found that "negatively parented" children are twice as likely to show delayed development of motor and social skills and three times as likely to be slow in acquiring vocabulary.
Dr Sheridan said the analysis of the data for low-income families revealed just how important positive parenting is for success in school.
Paul Kropp, author of I'll be the Parent, You be the Kid and The School Solution, thinks the study should lead to a re-thinking of public policy. "The study suggests that the old solution of throwing money at poor families or trying to improve the plight of teenage single moms is not sensible if your aim is to improve kids' chances for success. You're better off applying funds to programmes that help parents parent better."
The study can be found on www.statcan.caDailyEnglish 981028d981028. htm