IMPROVE AND CONDUCT THE COLLECTION, ASSESSMENT, AND DISSEMINATION OF FOOD CONSUMPTION AND RELATED DATA OF AMERICANS
Location: Food Surveys
Title: BLAISE INSTRUMENT DESIGN FOR AUTOMATED FOOD CODING
Submitted to: International Blaise Users Conference
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2004
Publication Date: April 15, 2004
Citation: Steinfeldt, L., Anderson, E. 2004. Blaise instrument design for automated food coding [abstract]. 9th International Blaise Users Conference Abstracts. Available: http://www.statcan.ca/english/conferences/blaise2004/abstracts.htm
The Automated Multiple Pass Method (AMPM) Blaise instrument, developed by the Food Surveys Research Group, Agricultural Research Service, U.S. Department of Agriculture, collects 24-hour dietary recall data. During the interview, individuals recall the foods and beverages that were consumed the day before the interview. Details about each food and beverage are collected as well as an estimate of the amount consumed. AMPM contains more than 2,500 questions and more than 21,000 responses. Ninety-five percent of the questions are about specific food details, including the amount of food eaten. The large number of questions and responses produce an even larger number of skip patterns because the questions asked about a food depends on the responses to the previous questions. The number of possible paths through the food detail questions is estimated to be over 400,000. The food detail information is used to assign food codes and calculate weights and nutrients for the foods reported consumed.
During the design of the instrument, careful attention was paid to how the food detail data would be stored in the Blaise database to insure that it could be extracted and used for manual and automated food coding. Foods were grouped into categories and the fields within each category were given a standard prefix. Across categories the same question, for example "What kind was it?", were given a standard suffix. Responses were written to be understandable to the food coder as well as the interviewer. Open-ended responses were limited by the use of over 90 look up tables. The use of standardized responses allows the creation of food coding paths. Food coding paths are unique sets of field names and responses reported for a specific food. Common paths could be used for automated food coding, while infrequently reported paths would be left to manual coding.
Initially, 10 commonly reported foods (e.g. milk) were linked with 28 food coding paths. These 10 foods produced an initial automated food coding rate of 11% of reported foods. Next, approximately 147,000 coded and approved foods were analyzed to determine commonly reported paths that could be linked to a single food code. The most common paths were selected, certified as correct by a nutritionist, and then incorporated into the Post Interview Processing System (PIPS). Currently 1,877 pathways linked to 964 foods are automatically coding approximately 48% of the foods reported.