 All studies were designed to analyze the impact of the program with respect to the previous food stamps program, focusing on changes in household nutrient availability, while the 1985 and 1993 studies also focused on changes in household food expenditures (the amount of money households spent on acquiring food).The first and most widely recognized study, published by Mathematica Policy Research, Inc. in 1985, found that the NAP program increased household food expenditures for beneficiaries when compared to non-participating families, just as its predecessor did.It also found that the program had the same relevant impact on increasing household food expenditures as the previous food stamp program, however this has been contested by subsequent studies performed on the national food stamp program, which found that "stamp" or "coupon"-type benefits are more effective at increasing food expenditures than direct "cash" benefits.