Screeners at a Glance

Purpose

To obtain basic information about a limited number of foods and beverages consumed or dietary practices over a period of time, typically the past month or year.

Description

Two types of approaches are primarily used for screeners, which are also called short dietary assessment instruments:

• A short food frequency questionnaire, usually without portion size questions.
• A behavioral questionnaire that asks about general dietary practices (for example, "Do you generally butter your bread?").

For both approaches, the questionnaire is usually self-administered, but can be interviewer-administered.

Completing a screener about specific dietary components or dietary practices usually requires less than 15 minutes.

See examples of frequency screeners.

See an example (PDF) of a behavioral screener [1].

Utility of Data

• Screeners yield information on consumption of queried foods and beverages or eating practices over a specific reference period.
  • Data can be used to assess particular aspects of diet but not total dietary intake.
  • Resulting estimates may be quantitative or qualitative, depending on the instrument.
  • If data are linked to a nutrient composition database, nutrient intakes can be determined (Learn More about Food Composition Databases for Food Frequency Questionnaires and Screeners).
  • If data are linked to a database that translates foods and beverages into food group equivalents, such as the Food Patterns Equivalents Database (FPED), foods and beverages reported can be disaggregated into their component ingredients, which can then be converted to equivalent amounts of relevant guidance-based food groups (For more information, read a factsheet on FPED products and associated data files or its application to dietary analysis.). This provides information about the consumption of food groups of particular interest, such as the total amount of fruits, vegetables, or added sugars. The frequency of consumption of food groups or pattern of eating practices can be used as indicators of particular aspects of diet.
• Frequency-type screeners are sometimes used to describe a population’s intake in [glossary term:] cross-sectional studies when interview time or resources are limited. This is not recommended because of the large [glossary term:] systematic error, a type of [glossary term:] measurement error (see Choosing an Approach for Dietary Assessment and Key Concepts about Measurement Error). Because of known [glossary term:] systematic error in the screener, a less biased [glossary term:] short-term instrument (e.g., 24-hour Dietary Recall (24HR)) may be administered in an [glossary term:] internal calibration sub-study to improve estimates of intake from the Screener (Learn More about Calibration).
• Screeners can be used to examine [glossary term:] associations between diet and other variables.
  • Screeners can be used in [glossary term:] retrospective case-control studies when interest is limited to a small number of dietary components rather than the total diet.
  • Because of their limited scope, screeners are seldom used as the main instrument in [glossary term:] prospective studies describing associations between diet and another factor.
• Frequency-type screeners are sometimes used in [glossary term:] intervention studies to monitor intakes of certain key dietary patterns or components (see Choosing an Approach for Dietary Assessment). Use of a screener (or any self-report dietary instrument) as the sole measure of change is not recommended when evaluating the intervention because of the potential for [glossary term:] differential response bias. This is of concern in intervention studies because [glossary term:] exposure to the intervention itself can create differential response bias in reporting in the treatment group(s) relative to the control group.

Limitations of Data

For frequency-type instruments:

• Because of the similarities between frequency-type screeners and Food Frequency Questionnaires (FFQ), the systematic error associated with FFQs (see Key Concepts about Measurement Error) is presumed to also affect data collected using such screeners. This error can be at least partially mitigated through appropriate statistical modeling, including [glossary term:] regression calibration (Learn More about Regression Calibration) or application of [glossary term:] scoring algorithms (Learn More about Scoring Algorithms for Screeners) using data from a less biased dietary assessment method as a [glossary term:] reference instrument.
• Detailed information about food preparation, specific food and beverages consumed, and brands, and contextual information about intake (e.g., which foods and beverages are consumed at the same meal) is lacking.
• Because a screener is composed of a pre-specified food list or set of behavioral questions, any single screener may not reflect the eating patterns of a given population. Thus, the performance of a particular screener in a particular population may not reflect its performance in a different population.

For behavioral-type instruments:

• The dimensions measured, which may include indices, have no meaning with regard to absolute nutrient or food intake other than ordering individuals in the population. For example, the Adolescent Food Habits Checklist (PDF) is composed of 23 true/false questions that are scored to derive an overall healthy eating behavior score.
• Use of procedures to score various dimensions of behavior developed in one population may not be appropriate in other populations [3-4].

Salient Features Compared to Other Self-Report Methods

For an at-a-glance comparison of the major features of self-report instruments for assessing diet, including Screeners, see the Comparing Dietary Assessment Instruments table.

• Captures past long-term diet (in contrast to 24HR and food record).
• Captures past intake of a limited number of foods or nutrients (in contrast to 24HR and food record).
• Usually self-administered (in contrast to interviewer-administered 24HR).
• Relies on [glossary term:] generic memory (in contrast to 24HR, which relies on [glossary term:] specific memory, and food record, which does not rely on memory).
• Not affected by [glossary term:] reactivity (in contrast to food record) (Learn More about Reactivity).
• Frequency-type screeners require ability to perform cognitively complex memory and averaging tasks (in contrast to 24HR and food record).
• Its major source of measurement error is systematic versus [glossary term:] random (in contrast to 24HR).