Improving food frequency questionnaires: a qualitative approach using cognitive interviewing.
In an attempt to improve data quality and ease of administration of standard self-administered food frequency questionnaires, various alternative approaches were tried for inquiring about frequency of consumption, portion size, seasonal intake, and food preparation. Evaluation consisted of a cognitive interviewing method in which respondents verbalize their thought process while completing several variations of a questionnaire. Interviewers observed and asked follow-up probe questions to evaluate problems or inconsistencies verbalized by respondents. Consensus and judgment by interviewers and observers suggested several problematic features of food frequency questionnaires: formatting of questions about frequency and portion size; computing average frequencies for aggregated food items or for foods eaten seasonally; comprehension of many items; and ordering of foods. These findings led to cognitive refinement and innovations, which included detailed questions regarding preparation or use of low-fat varieties or other alternatives to help better describe specifics of intake for some foods; questions on seasonal intake for several foods; inclusion of portion size ranges; and additional response categories for frequency of intake. Cognitive interviewing is an important step in pinpointing cognitive problems in dietary questionnaires.
Subar
A F
AF
National Cancer Institute, Division of Cancer Prevention and Control, Bethesda, MD 20892-7344, USA.
Thompson
F E
FE
Smith
A F
AF
Jobe
J B
JB
Ziegler
R G
RG
Potischman
N
N
Schatzkin
A
A
Hartman
A
A
Swanson
C
C
Kruse
L
L
D000368:Aged; D003071:Cognition; D015930:Diet Records; D004435:Eating; D005260:Female; D006801:Humans; D007407:Interviews as Topic / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires / Q000592:standards*