March of Dimes March of Dimes Peristats

Frequently Asked Questions

Q.

What are Confidence Intervals?

A.

Data from the Pregnancy Risk Assessment Monitoring System (PRAMS) are based on a sample of women in each state who have had a recent live birth. The rates of selected indicators reported are estimates of the value for all women who gave birth in that state in that year. The 95% confidence interval around the estimate is the range of values that have a 95% chance of containing the actual percentage for that indicator among all women in that state. When comparing percentages between groups (for example, comparing the percent of women who reported ever breastfeeding by race/ethnicity), differences would only be considered statistically significant if the 95% confidence intervals do not overlap one another.