The National WIC Evaluation: evaluation of the Special Supplemental Food Program for Women, Infants, and Children. VII. Study of food expenditures.

Recalls of monthly family food expenditure, taken before and after maternal WIC benefits, were obtained from 4,219 WIC and 785 control women; 1-wk expenditure diaries (at follow-up) were obtained from 1,031 WIC and 551 control women chosen randomly. Control families had higher incomes, spent more on groceries and in restaurants, and received fewer food stamp benefits. Women probably underreported the value of WIC benefits by recall (WIC vouchers are not dollar denominated). Although control families were more affluent, there were consistent effects of children's WIC benefits on weekly family grocery expenditure by diary ($6.10, p less than 0.05) and by recall ($2.14, p less than 0.01, and $1.48, p less than 0.05). WIC benefits to infants were associated with very large (but not significant) increments in grocery spending by diary ($7.57). WIC benefits to the pregnant woman were strongly associated with larger amounts of WIC food entering the household (as were infant and child benefits) but effects on grocery spending were unclear.