Both the number of children in poverty and the child poverty rate in America increased between 2008 and 2009, according to the U.S. Census Bureau, according to its national estimates of poverty released recently.

The number of children in poverty rose from 14.1 million to 15.5 million in 2009 and the child poverty rate increased from 19 percent to nearly 21 percent. In addition, the number and percentage of children living in "deep" poverty (households with incomes below 50 percent of the federal poverty level) also increased (from 6.3 million to 6.9 million and from 8.5 percent to 9.3 percent in 2009, respectively.)

Children made up more than a third (35.5 percent) of all people in poverty in 2009. These numbers represent an increase again over 2007 data, which reported 13.3 million children, or 18 percent, living in poverty in the United States.

A substantial body of research links poverty with multiple negative outcomes for children. When compared with children from more affluent families, poor children are more likely to have low academic achievement, to drop out of school, and to have health, behavioral, and emotional problems. These linkages are particularly strong for children whose families experience deep poverty, who are poor during early childhood, and who are trapped in poverty for a long time.

In 2009, a family of four including two children was considered to be living in poverty if their income was below $21,756. Despite the widespread use of the standard federal poverty level, many experts believe 200 percent of the federal poverty threshold is a better measure of economic hardship. Under this criterion, 42.2 percent of U.S. children lived in "low income" households in 2009.