Common Trend in WIC and Non WIC Breastfeeding Rate: A Cointegration Approach of Panel and Time Series Data

摘要

This thesis explores the trend of WIC (Women Infants and Children) and non WIC breastfeeding rates in U.S.A. WIC is a special supplemental nutrition program by USDA (United States Department of Agriculture).Time and panel data series have been used for 50 states of U.S.A and D.C (District of Columbia) to analyze the common trend between the two breastfeeding rates (time series data for 35 years and panel data series for 28 years).To determine the common trend, I used residual based cointegration for time series and recently developed error correction based cointegration for panel data series. I also constructed error correction models for both data series to evaluate the speed of adjustments between the two breastfeeding rates. The results suggest the prevalence of a common trend and moreover an upward trend for WIC and non WIC breastfeeding rates which indicates that both breastfeeding rates are growing together over time. The speed of adjustments toward equilibrium is faster in the time series data compared to the panel series data.