The number of children in foster care in Hawaii is at a 15-year low, the state Department of Human Services said Friday.

The number has declined 43 percent in the past five years, from about 3,000 to 1,700 children, the department said.

Human Services Director Lillian Koller attributed the decline to new strategies for strengthening at-risk families and assessing the safety of their homes.

Koller said prior to implementing the strategies, the state had been removing children from their biological families at up to four times the national average.

The state, which formerly used a "one-size-fits-all" approach, is now using a system that weighs the risk factors in a family's home.

The Differential Response system is Web-based and assists social workers with finding the least intrusive and most effective response for the child's safety.

Once the state determines the home is not safe and cannot be made safe, police immediately remove children and place them in custody. If the risk to the children isn't high, social workers help families to voluntarily resolve risk issues.

The state believes, whenever possible, children should be raised in their own families.

The state has also lowered foster care numbers by investing federal funds in poverty prevention programs. The services help parents find and retain employment and help young people succeed in school and avoid crime and drug abuse.

"We can see how providing families with support services before children are harmed has enabled families to stay together," said Darlene Beatty, an administrator for Catholic Charities Hawaii. "Therefore, children are not subjected to the challenges of foster care."

Now that social workers' caseloads have been lightened, they can spend more time assessing the needs of families and conducting home visits, state officials said.

On top of the fewer children in foster care, Hawai'i also has one of the lowest rates of child re-abuse in the country. The rate dropped from 6 percent in 2003 to 2.2 percent in 2007.