This study evaluates the differences between the Exact Affine Stone Index (EASI) demand model estimates obtained using Consumer Expenditure Survey (CEX) data and Nielsen Homescan data. Results indicated that elasticities obtained from CEX and Homescan data–based demand models differ not only statistically but also economically. Own-price elasticities obtained from the CEX data–based demand model were more inelastic than those obtained from the demand model estimated using Homescan data. Further, differences between expenditure elasticities did not follow a specific pattern. We found evidence suggesting that the main source of differences is the price index used for the estimation.