Scoring the By-Meal Screener


How to Score the Screener

Scoring the By-Meal screener is done in several stages. For the foods asked by meal (i.e., fruit, vegetables), an algorithm for converting the frequency information is used in conjunction with an algorithm for converting the portion size information to Pyramid/MyPyramid servings, ultimately resulting in estimates for fruits and other vegetables of daily number of Pyramid/MyPyramid servings/cup equivalents reported. For the remaining foods, a different algorithm for converting frequency information is used in conjunction with an algorithm for converting the portion size information.

These operations are described below, and implemented in the By-Meal Screener MyPyramid Cup Equivalents SAS Program and the By-Meal Screener Pyramid Servings SAS Program.

  1. For by-meal questions (q6-q11):
    1. Convert reported frequency by meal to average daily number of times consumed:

      For each fruit question (q6, q8, q10) and each vegetable question (q7, q9, q11), convert each frequency response category to the midpoint of that frequency range, and standardize to times per day per meal:

      Frequency Response Times Per Day
      Never 0.0
      1-3 days last month 0.067
      1-2 days last week 0.214
      3-4 days per week 0.5
      5-6 days per week 0.786
      Every day 1.0
    2. Assign fruit and vegetable Pyramid/MyPyramid servings for each portion size category.

      1. Using 2005 MyPyramid definitions of frnuit and vegetable cup equivalents:

        Food MyPyramid Cup Equivalents for each Portion Size Category
        1 2 3 4
        Fruit (units) .25 .5 1.0 1.5
        Fruit (cups) .25 .5 1.0 1.5
        Other Vegetables .25 .75 1.5 2.25
      2. Using 1992-2004 definition of Pyramid servings:

        Food Pyramid Servings for each Portion Size Category
        1 2 3 4
        Fruit (units) .75 1.0 2.0 2.5
        Fruit (cups) .75 1.0 2.0 2.5
        Other Vegetables .75 1.5 3.0 4.5
    3. Compute fruit and vegetable daily Pyramid/MyPyramid servings for fruit across all meals and for vegetables across all meals.

      For each food group for each meal, multiply the daily average frequency (from #a) by the portion size (from #b). Sum fruit across the three meals to estimate daily average number of Pyramid/MyPyramid servings from fruit. Sum vegetables across the three meals to estimate daily average number of Pyramid/MyPyramid servings from vegetables.

  2. For by-meal questions (q6-q11):
    1. Convert reported frequency by meal to average daily number of times consumed:

      For each fruit question (q6, q8, q10) and each vegetable question (q7, q9, q11), convert each frequency response category to the midpoint of that frequency range, and standardize to times per day per meal:

      Frequency Response Times Per Day
      Never 0.0
      1-3 days last month 0.067
      1-2 days last week 0.214
      3-4 days per week 0.5
      5-6 days per week 0.786
      Every day 1.0
    2. Assign fruit and vegetable Pyramid/MyPyramid servings for each portion size category.

      1. Using 2005 MyPyramid definitions of fruit and vegetable cup equivalents:

        Food MyPyramid Cup Equivalents for each Portion Size Category
        1 2 3 4
        Juice .5 1.0 1.625 2.5
        Lettuce salad .25 .5 1.0 1.5
        French Fries .2 .5 .75 1.3
        Other white potatoes .25 .75 1.2 2.0
        Dried beans .25 .75 1.25 2.0
        Tomato sauce .25 .5 1.0 1.5
        Vegetable soups .3 1.0 1.6 2.25
      2. Using 1992-2004 definition of Pyramid servings:

        Food Pyramid Servings for each Portion Size Category
        1 2 3 4
        Juice .75 1.33 2.17 3.33
        Lettuce Salad .5 1.0 2.0 3.0
        French Fries 1.25 2.3 3.1 4.8
        Other white potatoes .8 1.5 2.4 3.5
        Dried beans .75 1.5 2.5 3.5
        Tomato sauce .36 .72 1.45 1.7
        Vegetable soups .75 1.36 2.27 3.2
    3. Compute fruits and vegetable daily Pyramid/MyPyramid servings for each food group

      For each food group, multiply the daily average frequency (from #a) by the portion size (from #b).

  3. To estimate total daily number of Pyramid/MyPyramid servings, add across all foods.
  4. Note: Question 14 -- "How often over the past month did you eat mixtures that included vegetables?" -- is not included in this algorithm. This question may be helpful in identifying individuals who eat a lot of their vegetables in mixtures. If amounts of vegetables eaten in mixtures are harder to report, their reports may be somewhat less accurate. However, this supposition has not yet been tested.

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Earlier Changes in Scoring

On July 12, 2001, the following changes were made to the calculations used to estimate fruits and vegetables from the screener data:

  1. In the calculations to convert the frequency categories to number of times per day:
    • 1-3 times per month was changed from .066 to .067 times per day,
    • 3-4 times per week was changed from .499 to .5 times per day, and
    • 5-6 times per week was changed from .784 to .786 times per day.
  2. In the assignment of fruit and vegetable Pyramid servings to portion size categories:
    • the highest portion size category for juice was changed from 2.5 to 3.33 Pyramid servings and
    • the highest portion size category for lettuce was changed from 2.5 to 3.0 Pyramid servings

If you need the previous version of the SAS program, please send an e-mail to screeners@nih.gov.

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How to Handle Missing Data

  1. Assigning reasonable data to individual questions with missing answers:
    1. Frequency of intake for individual foods
      Assume Never=0 because many people do not fill in any bubble when they do not consume a food.

      If portion size for that item is answered and the frequency question is not answered, continue to treat as Never.

    2. Portion size
      Note: portion size is not missing if the frequency question stem above it is answered Never or assigned Never.

      If a vegetable, assign that individual's most frequently reported portion size category for all other separate vegetable questions. [Exclude "other vegetables" from this calculus because the portions reported there may reflect portions of all other vegetables rather than a single vegetable at a time.] In order to find the most frequently reported portion size category, weight each portion size category by the relative frequency with which each portion is reported, so that the portion sizes associated with more frequently consumed vegetables are given more weight than the portion sizes associated with less frequently consumed vegetables.

      If a fruit, assign the portion size category reported for the other fruit question. If neither fruit juice or fruit portion sizes are reported, assign the most frequently reported portion size for vegetables.

  2. Criteria for excluding cases (Note that these exclusion criteria are being developed, and may vary from study to study):
    • If frequency information on fruit or other vegetables is missing.
    • If nearly all questions are unanswered.
    • If more than one response to a question is provided.

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