About American Customer Satisfaction Index   Developed at the University of Michigan, the American Customer Satisfaction Index is a national economic indicator of customer evaluations of the quality of products and services available to household consumers in the United States. It is updated each quarter with new measures for different sectors of the economy replacing data from the prior year. The overall ACSI score for a given quarter factors in scores from about 200 companies in 44 industries and from government agencies over the previous four quarters.