Once the first three steps have been completed for a
study, or for one year of What We Eat in America, Survey
Net calculates preliminary nutrient intakes for the 24-h
recalls, and the final quality assurance phase is conducted
using the aggregate data. Checks are run separately for the
following groups: adult males, adult females, males 12–19,
females 12–19, children 6–11 and 1–5, and infants. Within
each group, 24-h recalls with daily intakes above the 99th
percentile for a nutrient are identified and reviewed to
determine the food source of the nutrient. Unusual cases
are investigated. For example, when the source of a very
high vitamin E intake was identified as tomato and
vegetable juice, it was found that the database value was
based on samples of the food which were fortified with
vitamin E. The database value was corrected before the
final nutrient analysis. During this quality assurance phase,
mean intakes of nutrients and food groups for the above
gender/age groups are also compared with intakes from
previous years or other similar surveys. Unusually high or
low values are investigated.