Most SEL research answers a version of the same question: what happens when you teach kids these skills? There's a different, harder question worth asking directly: what happens to the kids who never get taught them at all — not next year, but twenty years from now?
One study answered that question about as rigorously as social science ever manages to. Here's what it found.
The 19-Year Study That Tracked Kindergartners Into Adulthood
In 2015, researchers Damon Jones, Mark Greenberg, and Max Crowley published a study in the American Journal of Public Health that remains one of the most cited pieces of evidence in this entire field. Drawing on the Fast Track study, they followed more than 700 children from lower-income communities across three cities and one rural area, starting in kindergarten and tracking outcomes 13 to 19 years later, through to age 25.
The starting measurement was almost deceptively simple: kindergarten teachers rated each child on a handful of ordinary social behaviours — whether the child was helpful to others, shared materials, listened to peers, and could resolve small problems independently. Nothing dramatic. Just the everyday texture of getting along with other five- and six-year-olds.
That single early rating, taken before these children had learned to read fluently, turned out to predict outcomes across their next two decades with genuine statistical significance — even after researchers controlled for family income, academic ability, and a wide range of other background factors.
What the Data Actually Showed
The associations, tracked into early adulthood, spanned domains most people don't automatically connect to a kindergartner's social skills:
- Education: Children with higher kindergarten social competence scores were roughly twice as likely to graduate from college, and meaningfully more likely to complete high school at all.
- Employment: Higher early social competence was associated with being 46% more likely to hold a full-time job by age 25.
- Criminal activity: Lower early social competence was linked to a significantly higher likelihood of arrest and involvement in the criminal justice system by early adulthood.
- Substance use: Children who scored lower on kindergarten social competence showed higher rates of substance use problems later in life.
- Mental health: Early social-emotional skill deficits were associated with a greater likelihood of emotional and behavioural difficulties tracked into adulthood.
One point in a kindergarten social competency rating — a single-digit shift on a simple five-point teacher scale — carried statistically meaningful weight across all five domains, tracked nearly two decades later.
The Honest Caveat This Study Deserves
It's worth stating plainly, because the researchers themselves did: this study demonstrates a strong statistical association, not proof of direct causation. Damon Jones, the study's lead author, was explicit that the findings alone don't prove that low social competence directly causes worse adult outcomes — a child's social skills in kindergarten are shaped by family environment, community context, and countless other factors that also independently influence adult outcomes.
What the study does establish, robustly, is that kindergarten social-emotional skill is one of the strongest early markers researchers have found for a child's long-term trajectory — strong enough that it held up even after statistically accounting for many of those other factors. That's not the same as saying "teach a child to share and you'll guarantee them a college degree." It is saying that social-emotional skill deficits observable as early as kindergarten are a genuine, measurable risk signal worth taking seriously, not a minor developmental footnote.
Why the "Compounding" Framing Matters More Than a Single Study
This finding doesn't stand alone. It sits alongside a broader body of longitudinal research — including well-known work tracking childhood self-control into adulthood — pointing toward the same underlying pattern: social-emotional skill gaps in early childhood don't stay contained to early childhood. Without intervention, they tend to compound. A child who struggles to resolve a playground conflict at six doesn't automatically develop the ability to navigate a workplace disagreement at twenty-six. The skill gap, left unaddressed, has a tendency to simply travel forward with the child, showing up in progressively higher-stakes settings as they age.
This is the real argument for early, intentional SEL instruction — not that it's a nice-to-have enrichment activity, but that the alternative isn't neutral. A child who doesn't build these skills isn't simply "developing at their own pace" toward the same destination. The evidence suggests they're heading toward a measurably different set of long-term odds.
What This Means for Parents and Schools
The good news buried in this research: if a lack of early social-emotional skill is a strong early predictor, it's also, by definition, a genuinely early opportunity for intervention — long before the compounding effects the study documented have had years to accumulate.
For parents: kindergarten and early primary years are not too early to take social-emotional development seriously. A child who struggles to share, take turns, or resolve small conflicts at five isn't just going through a normal phase to ignore — it's worth active, deliberate attention, the same way you'd take an early reading struggle seriously rather than assuming it will simply resolve itself.
For schools: this is precisely the evidence base behind treating SEL as core curriculum rather than an optional add-on. A kindergarten teacher's simple, ordinary observations about how a child gets along with peers may be one of the more genuinely predictive pieces of information a school has about that child's next two decades.
What to Do With This
- If your child is young, treat social skill struggles with the same seriousness as an academic struggle — not as something they'll simply grow out of unassisted.
- Ask your child's school directly how early social-emotional skills are actually assessed and supported, not just whether an SEL program technically exists somewhere in the curriculum.
- Remember the direction of the finding: early intervention is exactly where this research suggests the highest leverage lives — the earlier the skill gap is addressed, the more of the compounding effect gets interrupted before it accumulates.
The kids in that 19-year study who struggled most in kindergarten weren't destined for worse outcomes by nature. They were simply the ones who never received the intervention this entire body of research argues for. That's the actual takeaway — not a verdict on any individual child, but a clear case for not waiting.
Happy Sprout Action: Want to give your child the early social-emotional foundation this research points to, well before those small early skill gaps have a chance to compound? Register your child for a live Happy Sprout SEL class at happysproutminds.com and start building these skills now, guided by a trained facilitator.
Future Starts Within.
