Methods
Linking Nielsen Scantrack (Sales) and Homescan
(Purchase) Data to NFL Data
To determine total caloric sales, NFL data were linked with Nielsen Scantrack UPCs, as well as Nielsen Homescan UPCs (for adjusting the Scantrack data). This linking strategy reliably accounted for 95.1% of the total volume sales in 2007 and 97.2% of 2012 volume sales from Scantrack, of which HWCF products were reliably matched for 99.2%–99.5% by volume (Appendix A, available online). Mutually exclusive food (51) and beverage (11) categories were used for examining key calorie sources (Appendix B, available online). The food and beverage categories were based on Nielsen-developed modules that reflect product placement in stores and are not nutritionally based. Future analyses looking at the effects of the decline in calorie sales on children’s diets will base categorizations on U.S. Department of Agriculture (USDA)–defined food and beverage groups.37