It’s a concept that parents may not be familiar with, but experts say it can explain a lot about family conflicts: Is your child’s temperament a good “fit” with yours?

For example, a stubborn child who’s a chip off the old block might have a lot of showdowns with an equally stubborn mom or dad. But contrasting temperaments don’t necessarily assure good results: A determined child might overwhelm an overly flexible parent.

Many personality traits such as these are inborn, but “temperaments can also be colored by the environment in which children are raised,” said child psychologist Brian Daly, who teaches at Drexel University in Philadelphia.

That means parents who take a step back to consider their child’s personality traits may be able to tailor their childrearing style to deal more effectively with problems.

Much of the research on child temperament is based on the New York Longitudinal Study, in which psychiatrists Alexander Thomas and Stella Chess followed a group of children from birth to adulthood beginning in 1956. Thomas and Chess, who were married, found that children’s personalities could be put in three basic categories: easy, difficult, and slow to warm up. They also identified nine other variables that measured behaviors and traits such as willfulness, moodiness, activity levels, distractibility, attention span, and regularity in sleep, hunger and other biological functions.

One finding from their research was that a good “fit” between children and parents results when adult expectations, values and demands are in accord with a child’s natural capacities and behaviors. Their last book, published in 1999, was called Goodness of Fit. (Thomas died in 2003, Chess died in 2007.)

But their theory was not just a way of letting parents off the hook by blaming kids for personality traits they could not control. The takeaway for parents was that conflicts resulting from a poor fit between parent and child might be ameliorated if childrearing practices could be changed. The theory has withstood the test of time, with psychologists and other experts who work with children and parents still using some of these concepts today.

Resa Fogel, a psychologist who practices in Montclair and Teaneck, N.J., was one of the children in the original study. “When I was little, they came to my house all the time and interviewed and watched me,” said Fogel. “They were the nicest people. I thought they were another set of grandparents.”

She became interested in psychology, an interest that was fueled when she got a job assisting Thomas in his research at New York University. She used some of the original studies for her dissertation, which looked at how children with difficult temperaments end up behaving.

“You would think people with difficult temperaments are automatically very hard people to be around,” she said. “I showed that if there’s a goodness of fit between the environment and the person, then even if you have a difficult temperament, you’re not going to necessarily misbehave. In other words, there’s hope for people who are tough.”

Difficult children “are going to be harder” for parents, she acknowledged, “but you have to have the right way of handling it. That’s what goodness of fit is. It’s like a puzzle you put together.”

Arthur Robin, director of psychology training at the Children’s Hospital of Michigan in Detroit, said one common problem he encounters is a child with ADHD or “a very hyper-impulsive child” who has “a passive, depressed, lethargic mom. The child is going to get to do anything he or she likes because the mom is not going to have the energy level to set down some structure.”

Another common problem is “a very rigid, willful child and a highly flexible parent,” Robin said. “The parent is going to go with whatever the child wants. The child is going to end up really spoiled or have a strong sense of entitlement.”

The parents

Sometimes problems are rooted in the temperament of the parent, not the child. “If a parent is extremely moody, and a child is not very even-tempered, the child is going to get really upset and scared, and may develop in an introverted manner because they can’t deal with the extremes of parent moodiness,” Robin said.

With willfulness, Robin says, he tries to recast the trait as “determination” and encourages parents to channel it into “positive activities to move the child ahead.” Teenagers might be encouraged “to fight for some kind of cause, or sometimes parents can get them to spend a lot of time on creative pursuits, so it’s not all channeled into conflicts with parents.” Music or artistic pursuits may be an especially good outlet for moody children, Robin said.

Daly said he often encounters families where parents have no problems with one child but a lot of problems with the other. “One child is very well-behaved and fits their parenting style,” he explained. “You could say the child’s temperament is a good match or fit. They rave about that child; the child is responsive and respectful.”

But with the other child, the parents may feel that they’re “constantly butting heads. There may be temper tantrums, digging in heels, but without an appropriate result. A lot of times parents have certain values and it can be hard to adjust those values to meet the temperament of the child.”

Choose your battles

Daly said parents who are just as stubborn as their kids often get into standoffs because “neither will give ground.” In these cases, it may not work to take a hard line approach of, “if you can’t comply with this, then you’re going to get in more and more trouble.”

It also pays to pick your battles carefully. When a little girl couldn’t get out of the house without a tantrum over what to wear, Daly counseled her parents to let her choose her own outfits even if they weren’t quite as coordinated as the parents wished.

With teens, said Robin, if they’re “sneaking out in the middle of the night,” you have more important things to focus on than whether their room is clean. “The stuff that isn’t worth fighting about, let it drop,” Robin said.

Another thing to keep in mind when a child’s personality presents challenges, Fogel said: “This is the temperament she was born with; this is how she acts, this is how you act. You try to find a way to make things better but there’s no magic answer, there’s no formula.”