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373 – Contributed Oral Poster Presentations: Quality and Productivity Section
A Revised Sampling Plan for Obtaining Food Products for Nutrient Analysis Under the National Food and Nutrient Analysis Program: Selection of Sampling Locations
Charles Perry
USDA
Pamela Pehrsson
USDA
Marlon Daniel
USDA
The Nutrient Data Laboratory (NDL) of the United States Department of Agriculture (USDA) implemented the National Food and Nutrient Analysis Program (NFNAP) in 1998. The goal of this program was to obtain nationally representative estimates of the nutritional components of common foods consumed in the United States for inclusion in the USDA National Nutrient Databank System.
This design, like the previous 2001 design, employs a three-stage, stratified, probability-proportional-to-size (PPS) sample selection process. Using this method will result in a self weighting sample of population centers, ensuring geographic dispersion across the 48 conterminous states; 48 locations were selected, with nested subsets of 24, 12 and 6 locations.
Increased penetration of warehouse-type retail outlets into the grocery industry, we adjusted the sampling frame to include these purchase locations. This will ensure that food samples which are collected according to this statistically rigorous sampling approach are consistent with national representativeness and allow better estimates of the mean and variability than convenience sampling or less rigorous options.