About 8.3 million children under age 19 in the United States, or 10.4% of children in this age group, had no health insurance for at least some of 2009. (Similarly, about 10.3% of children in this age group had no health insurance for at least some of 2008.) Uninsured children are, on average, less likely than insured children to have the recommended number of well-baby and well-child medical visits and less likely to receive standard immunizations. Children without health insurance also rely more on hospital emergency rooms for basic care and therefore receive such care in the least cost-efficient manner. A child's health insurance status depends largely on decisions made by his or her parents or guardians, and is highly dependant on whether these adults receive employer-sponsored coverage. If the child's parents receive employer-sponsored coverage, it is likely that the child will as well. For those children not covered by their parents' (or guardians') employer-sponsored insurance, public may be programs available. Medicaid is a means-tested entitlement program that finances the delivery of primary, acute, and long-term medical care. Each state designs and administers its own version of Medicaid under broad federal rules. The state Children's Health Insurance Program (CHIP) allows states to cover targeted low-income children with no health insurance in families with incomes above Medicaid eligibility levels. States may enroll targeted low-income children in CHIP-financed expansions of Medicaid, create new separate state CHIP programs, or devise combinations of both approaches. A small number of children without employer-sponsored coverage, Medicaid, or CHIP may have other health insurance coverage. Some disabled children are eligible for Medicare. Other children have insurance from policies purchased in the small-group market or from policies granted as a part of military benefits. This report examines the health insurance status of children under age 19 in 2009. Following a brief discussion of the data, the report looks at the relationship between the types of health insurance held by a child and the characteristics of the child and his or her parents (including age, other demographic characteristics, and ties to the labor market). Next, the report demonstrates the different conclusions that might be drawn from different analyses of the childhood uninsurance data. The report concludes with a discussion of trends in insurance status since 1999 for children under age 18; comparable data exist for years been 1999 and 2009, inclusive. This report uses 2009 data collected in the 2010 Current Population Survey (CPS) conducted by the Census Bureau of the U.S. Department of Commerce. The CPS is a monthly survey of non-institutionalized civilian households used primarily to collect employment data. The Annual Social and Economic Supplement (ASEC) to the CPS collects information on individual health insurance status, income, and poverty. The ASEC is also known as the March Supplement, because most of the surveys are completed in March, with many questions covering the prior year. About 100,000 addresses comprise the sample households to be interviewed. Statistical techniques adjust the data to represent all households in the nation. The March Supplement to the CPS is one of several widely used sources used to estimate the levels of uninsurance in the United States. The key variable in this report is whether each child was uninsured in 2009. More specifically, the uninsurance variable measures whether the child lacked health insurance for at least some part of 2009. This report, therefore, uses the term "uninsured" to mean uninsured at a point in 2009, not necessarily uninsured over the entire year. This section covers the relationships between health insurance and a child's and/or parent's demographic and employment characteristics. Table 1 reports the insurance status of children according to their personal characteristics. Looking at age, the percentage of uninsured children in 2009 ranged from 9.2% for children under age 6 to 12.5% for children between 13 and 18 years old. The percentage of children with public insurance decreased with the age of the child, while the percentage of those with employer-sponsored coverage increased with age. The percentage of children with employer-sponsored insurance was 52.1% for those children under age 6 compared with 60.6% for children between 13 and 18 years old. Of those children under age 6, 39.9% had public insurance, while 26.9% of children between 13 and 18 years old had public insurance in 2009. Examining differences in insurance across race and ethnicity indicates that uninsurance rates were highest among Hispanic children (17.5%), who had the lowest employer-sponsored coverage of any race/ethnic group (35.0%). On the other hand, uninsurance rates were lowest among white children (7.3%) who had the highest employer-sponsored coverage of any race/ethnic group (69.4%) Children who were black or Hispanic were more than twice as likely to have public coverage than children who were white or Asian. Children were less likely to be uninsured if they lived in the Northwest or Midwest (7.3% and 7.8%, respectively) than if they lived in the South or West (13.0% and 11.0%, respectively). Employer-sponsored health insurance covered about 63% of children in the Northeast and Midwest, and about 53% of children in the South and West. Citizens are more likely to have employer-sponsored coverage than noncitizens. Native-born and naturalized children had similar rates of employer-sponsored health insurance, at 57.7% and 58.3%, respectively. On the other hand, only 31.4% of children who were not citizens had employer-sponsored insurance. As shown in Table 2 , insurance coverage among children under age 19 who lived with at least one parent also differed by family structure. Approximately 8% of children living in a two-parent family were uninsured in 2009, compared with 12% of children living with a single mother and 16% of children living with a single father. Although children living with a single father were more likely to have employer-sponsored health insurance than those living with a single mother, children living with a single father were more likely than those living with a single mother to be uninsured because they were less likely to have public coverage. Private health insurance coverage varies with income. Among children in families living below the poverty threshold, 14.4 % had employer-sponsored coverage, 73.7% had Medicaid or other public coverage, and 14.7% were uninsured. As family income increased, children were more likely to have employer-sponsored coverage and less likely to have public coverage. A child's source of health insurance is strongly associated with his or her parents' coverage. Approximately 90% of children who lived with a parent with employer-sponsored coverage also had employer-sponsored coverage. Likewise, 97.4% of children who lived with a parent with public coverage also had public coverage. However, among children who lived with an uninsured parent (or parents), 41.2% were uninsured, but 52.8% had public coverage. This last difference could reflect the fact that children are more likely than their parents to be eligible for Medicaid and CHIP. As shown in Table 3 , among children under age 19 who live with at least one parent, there is a relationship between the insurance status of the child and the employment characteristics of the parent(s). In 2009, of those children with at least one parent working full-time for the entire year, 71.2% had employer-sponsored health insurance and 8.2% were uninsured. Of those children with at least one parent working part-year and/or part-time, 31.6% had employer-sponsored health insurance and 12.8% were uninsured. Public insurance coverage filled some of the gaps for those without employer-sponsored coverage. Public rates were 20.7% for children with a parent who worked full-time and full-year, and almost triple that (58.2%) for children whose parents were less attached to the labor force. As is usually the case, employer-sponsored coverage was less common for workers in small firms than for workers in larger firms. Employer-sponsored coverage rates were 27.4%, and uninsurance rates were 20.6% among children when the primary worker was in a firm with fewer than 10 employees. On the other hand, employer-sponsored coverage rates were 76.3%, and uninsurance rates were 5.0% among children when the primary worker was in a firm with at least 1,000 workers. This section demonstrates that, in evaluating groups of uninsured children, it is important to decide on an appropriate comparison group. Although family status for children living with at least one parent is used as an example, the issues covered in this section are applicable to other traits as well. The conclusion is that different representations of the same data can lead to different conclusions if care is not taken when evaluating the data. Figure 1 looks at the total number of uninsured children and displays the percentage of uninsured children living with at least one parent by family structure. From this picture alone, one could conclude that uninsurance was highest among two-parent families. This is because almost 60% of the total pool of uninsured children live with two parents, while about 31% of the total pool of uninsured children live with a single mother, with the remaining 11% living with a single father. In this example, it is important to remember that all comparisons are relative to the total number of uninsured children. Different conclusions, however, might be drawn if the analysis compares the percentage of uninsured children within each group's family structure. These comparisons are illustrated in Figure 2 for two-parent families, single-father families, and single-mother families, respectively. Even though Figure 1 shows that those living in two-parent households are the largest group of uninsured children, Figure 2 demonstrate that children living in two-parent families are less likely to be uninsured than children living with only one parent.