This article is about one of the most interesting studies of how to raise successful kids I've ever seen--and I've seen a lot of them.

It's not without its flaws, and we'll get to them. But, the sheer length of the time involved in the data collection, and the fact that it relies on external and objective data--rather than what the kids involved reported themselves--makes its conclusions fascinating.

Writing in the journal JAMA Pediatrics, the researchers from the University of Montreal set out to learn "which disruptive behaviors in kindergarten are associated with employment earnings in adulthood for boys from low socioeconomic backgrounds."

They tracked nearly 1,000 boys over 30 years--correlating their teachers' assessments of their behavior in 1984, when they were 5 or 6, with their adult earnings decades later (which they obtained from their tax returns as 35 and 36-year-old adults).

What they discovered could have significant implications for the way parents -- especially parents of boys -- view their children's behavior at an early age.

The 'Social Behavior Questionnaire'

The boys who paid better attention in school and showed other similar behaviors as young children wound up making much more money down the road. That leads to some key suggestions for both parents and schools on how to react to young children.

Using a set of behavior ratings ("the well-validated Social Behavior Questionnaire"), the kindergarten teachers in the program assessed the boys in four negative areas, and one positive one: 

• Inattention ("poor concentration, distracted, head in the clouds, and lack of persistence")

• Hyperactivity (those who were assessed as "agitated/fidgety and moves constantly")

• Opposition ("disobeys, does not share materials, blames others, inconsiderate, and irritable")

• Physical aggression ("fights with other children, bullies/intimidates other children, and kicks/bites")

• Prosociality, which included things like "helping, sharing, and cooperating," and whether they were the type of children who would "[try] to stop quarrels or disputes, ... invite bystanders to join in a game, and ... try to help someone who has been hurt."

They kept assessing the boys "yearly until age 17, then less regularly afterwards," the study's lead author, Richard Tremblay, told me in an email.

Their JAMA Pediatrics paper, however, focused on one specific correlation: the kindergarten data collection, and their tax return information three decades later, as grown men.

A clear correlation

Here's the one-sentence takeaway: Children who were rated by their teachers as more "prosocial," and had fewer assessments of inattention, hyperactivity, opposition and physical aggression, made significantly more money three decades later.

On average: $12,000 more. As you might expect, it's a bell curve; the children rated highest by kindergarten teachers (more positive assessments) wound up making as much as $17,000 more per year than the ones in the lowest quarter.

In fact, the highest paid 36-year-old from the class was making just over $142,000 a year at the time of the income assessment--while there was at least one at the other end of the spectrum, who had literally zero income.

Interestingly, this was a study of children in Montreal, and it could probably never have been done in the United States, since we're apparently a lot more serious about keeping tax returns private than Canada is. (Although Tremblay and the other study authors told me they thought the results would likely be the same for American kids, too.)

What about the girls?

It's interesting work for sure -- but I found myself scouring the journal article to ask the obvious question--one you might find yourself asking, too: Why didn't they also track girls?

So when I reached out to all three study authors, that was my first question. 

"The original interest was understanding the development of juvenile delinquency," Tremblay told me, "and boys from low [socioeconomic status]  environments are much more at risk."

But he added that the researchers also started a much larger, random study in 1987, focusing on both boys and girls.

"We are presently analyzing these data and will have results for boys and girls from the whole population," he said. So stay tuned, in other words, for research on the other half of the population.

The takeaways and advice

I'll give Tremblay credit for one other thing, which is that he didn't shy away when I asked him what lessons we should take from this work. Often, study authors will pull back if you push them on what to do with their research.

But he had two specific suggestions. First, he said that "quality day care" has been shown to decrease the prevalence of a whole host of negative, long-term problems for kids who show signs of struggle.

And second, he said that some of the "most aggressive and hyperactive" kindergarten boys in the study were selected for a program that gave extra support for two years to the students, their parents and their teachers--and it was very successful.

Those who were in the support program for two years wound up with:

• reduced drug use and delinquency during adolescence, 

• increased high school completion and 

• reduced criminal convictions by 24 years of age--compared to their peers who didn't get the extra support.

All things considered, it suggests that the way our kids act as kindergartners might predict what they'll be like when they get older, but it's not written in stone. If we want our kids to grow up to be successful, it's up to us to give them the support they need now.

Photo credit: FreeImages.com/Niels Rameckers. An earlier version of this article appeared on my column on Inc.com.`