A study co-authored by Dartmouth economics Professor Patricia Anderson found that the more hours a child's mother works outside the home, the more likely it is that the child will become overweight. Working with Kristin Butcher of the Federal Reserve Bank of Chicago and economics Professor Phillip Levine of Wellesley College, Anderson's study -- entitled "Maternal Employment and Overweight Children"-- discovered that a mother's time constraint increases the probability of her children becoming overweight. Levine said that maternal employment is only "one factor in the increase of childhood overweight" and "does not explain most of the trend" in overweight children. Their research found that increasing levels of maternal employment between 1975 and 1999 can explain 6 to 11 percent of the growth in childhood overweight. Levine explained that their research was motivated by recent media attention alluding to a link between working mothers and overweight children. From 1975 to 1999, the average hours worked by mothers increased by 7.5 hours per week while levels of overweight among children ages six and older rose from roughly 5 percent to over 13 percent.