WASHINGTON — In a wide-ranging look at how children have fared in their first decade of life, a study to be released today offers a promising picture of American childhood: Sixth-graders feel safer at school. Reading and math scores are up for 9-year-olds. More preschoolers are vaccinated. Fewer are poisoned by lead.

The analysis, which created a composite index of more than 25 key national indicators, reports a nearly 10 percent boost in children's well-being from 1994 to 2006. This overall improvement comes in spite of two significant downtrends: a worsening in rates of childhood obesity and in low-birth-weight babies.

"There are some really encouraging signs of progress," said Ruby Takanishi, president of the nonprofit Foundation for Child Development, which funded the research. "I think it's important as a country ... to see that there are things that parents can do, that government can do, that institutions can do, to make measurable differences for children."

Experts familiar with the report credited shifts in government policy, in the economy and in parenting for the advances highlighted in the study, done by Kenneth Land, a Duke University sociologist and demographer. But they also cautioned that significant problems remain and that the recent economic downturn could take a toll.

Andrew Cherlin, a professor of sociology and public policy at Johns Hopkins University, noted that the greatest progress tracked by the report occurred before the nation's economy slowed in 2001. "With the economy weakening further, we may see an additional slowing of the improvement or perhaps even some backsliding," he said.

The report brought together a broad collection of mostly federal data. In some cases, calculations were done for missing years.