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Multifactor Screener in OPEN: Scoring Procedures

How Analytical Scoring Procedures Were Developed

Scoring procedures were developed to convert a respondent's screener responses to estimates of individual dietary intake for percentage energy from fat, grams of fiber, and servings of fruits and vegetables, using USDA's 1994-96 Continuing Survey of Food Intakes of Individuals (CSFII 94-96) dietary recall data. The following equations were estimated in the CSFII 94-96:

For percentage energy from fat and fiber:

E(Dietary Factor) = b0+ b1NFG1P1 + b2NFG2P2 + … + b19NFG19P19

E(Dietary Factor) indicates the expected values for percentage energy from fat and for fiber, and assumes a normal distribution. In the CSFII 94-96 dataset percentage energy from fat was normally distributed. However, fiber was positively skewed and required a cube-root transformation to approximate normality. NFGk is the usual number of times per day an individual consumed food group k; Pk is the median portion size of group k; and k indexes the 19 food groups. These 19 food groups were formed to reflect the same food groups on the screener. We calculated weighted least-squares estimates of the regression coefficients bk, k = 0, …, 19 on CSFII 94-96 adults aged 18 and above, stratifying by gender and excluding extreme exposure values. We first included all 19 food groups in the regression model. After examining the results, we dropped food groups that failed to attain statistical significance at the α = 0.25 level to form more parsimonious final models. In both the percentage energy from fat model and the fiber model, the lettuce food group was dropped. Because of the complex survey design, the analysis was performed using SUDAANExternal Web Site Policy (RTI Inc., Research Triangle Park, NC).

For Pyramid servings of fruits and vegetables (defined by USDA in the 1992 Dietary Guidelines Food Guide Pyramid):

E([Fruits and Veg]1/2) = b0 + b1 ([NFG1P1 + NFG2P2 + … + NFG7P7]1/2)

Pyramid servings of fruits and vegetables was square-root-transformed to approximate normality; NFGk is the usual number of times per day an individual consumed food group k; Pk is the median portion size of group k; and k indexes the 7 fruit and vegetable food groups. We calculated weighted least-squares estimates of the regression coefficients b0 and b1 on the adults in the CSFII 94-96 sample, stratifying by gender and excluding extreme exposure values.

Scoring Procedures

  1. Estimation of NFGk: Express each reported frequency as a daily average. To do this, standardize the midpoint of each frequency category to the number of times per day.

    Frequency Response Times Per Day
    Never 0.0
    1-3 times per month 0.067
    1-2 times per week 0.214
    3-4 times per week 0.5
    5-6 times per week 0.786
    1 time per day 1.0
    2 times per day 2.0
    3 times per day 3.0
    4 or more times per day 4.5

  2. Estimation of Pk: The median age- and gender-specific portion sizes for each food were estimated from CSFII 94-96. For percentage energy from fat and fiber variables, the units were in grams (Tables 1-2); for fruit and vegetable servings variables, the units were in Pyramid servings (Table 3).

    A Pyramid serving is defined by the U.S. Department of Agriculture in the Dietary Guidelines Food Guide Pyramid (used from 1992-2004) as:

    • vegetables: 1 cup raw leafy, ½ cup of other vegetables, or ¾ cup vegetable juice; and
    • fruit: 1 whole fruit, ½ cup of cut-up fruit, or ¾ cup fruit juice.

    Note: current dietary guidance uses cups rather than servings.

    Table 1. Median Portion Size (Pk) in Grams per Mention by Age for Percentage Energy from Fat and Fiber Analyses: Men
    Food Group Age Group
    18-27 28-37 38-47 48-57 58-67 68-77 78-99
    Men
    Cold cereals (P1) 74.666667 61.500000 57.500000 56.000000 46.000000 39.000000 33.000000
    Whole milk (P2) 305.000000 259.250000 306.710000 244.000000 244.000000 244.000000 203.333333
    2% milk (P3) 259.250000 305.000000 244.000000 244.000000 244.000000 183.000000 183.000000
    1% milk (P4) 341.600000 245.000000 245.000000 244.000000 213.500000 223.666667 183.000000
    Skim milk (P5) 366.666667 250.000000 250.000000 245.000000 214.375000 198.937500 160.725000
    Bacon or sausage (P6) 25.000000 40.250000 32.000000 32.000000 27.000000 26.000000 24.000000
    Hotdogs (P7) 114.000000 85.500000 88.000000 114.000000 57.000000 57.000000 57.000000
    Whole grain bread (P8) 56.000000 54.000000 52.000000 52.000000 51.000000 48.250000 48.000000
    100% fruit juice (P9) 372.000000 311.250000 249.000000 249.000000 248.000000 186.750000 186.750000
    Fruit (P10) 131.750000 128.000000 123.200000 127.500000 122.000000 118.000000 114.250000
    Salad dressing (P11) 23.543333 23.626667 22.030000 27.500000 24.585000 19.285000 15.600000
    Fried potatoes (P12) 112.500000 114.000000 100.000000 100.000000 85.500000 85.500000 97.000000
    Other white potatoes (P13) 210.000000 196.000000 184.000000 161.000000 145.000000 127.000000 107.000000
    Dried beans (P14) 180.000000 130.000000 172.000000 172.000000 158.125000 175.000000 170.100000
    Other vegetables (P15) 60.013333 73.000000 74.063333 79.833333 76.500000 73.000000 67.520909
    Pasta (P16) 330.000000 280.000000 280.000000 247.500000 280.000000 210.000000 210.00000
    Nuts (P17) 31.625000 58.000000 35.500000 54.665000 39.250000 17.130000 35.916667
    Chips (P18) 40.000000 40.000000 31.895000 30.000000 26.000000 21.000000 17.500000

    Table 2. Median Portion Size (Pk) in Grams per Mention by Age for Percentage Energy from Fat and Fiber Analyses: Women
    Food Group Age Group
    18-27 28-37 38-47 48-57 58-67 68-77 78-99
    Women
    Cold cereals (P1) 50.000000 49.500000 44.000000 43.500000 33.000000 33.000000 33.500000
    Whole milk (P2) 244.000000 244.000000 244.000000 244.000000 198.250000 198.250000 196.400000
    2% milk (P3) 244.000000 244.000000 244.000000 244.000000 183.000000 183.000000 152.500000
    1% milk (P4) 244.000000 244.000000 183.000000 152.500000 183.000000 183.000000 218.583333
    Skim milk (P5) 245.000000 245.000000 244.800000 229.690000 196.000000 183.750000 183.750000
    Bacon or sausage (P6) 26.000000 25.000000 24.000000 24.000000 18.000000 19.500000 16.000000
    Hotdogs (P7) 57.000000 57.000000 57.000000 114.000000 57.000000 57.000000 57.000000
    Whole grain bread (P8) 50.000000 48.000000 47.500000 45.000000 45.000000 42.400000 34.000000
    100% fruit juice (P9) 280.125000 249.000000 248.800000 233.250000 189.755000 186.600000 186.700000
    Fruit (P10) 118.000000 118.000000 118.000000 118.000000 118.000000 112.427143 109.000000
    Salad dressing (P11) 17.140000 20.626667 23.020000 21.873333 22.035000 18.335000 10.210000
    Fried potatoes (P12) 79.500000 70.000000 70.000000 70.000000 66.000000 70.000000 64.000000
    Other white potatoes (P13) 122.000000 127.000000 116.000000 122.000000 105.000000 105.000000 105.000000
    Dried beans (P14) 126.500000 89.000000 126.500000 126.500000 126.500000 126.500000 173.000000
    Other vegetables (P15) 53.750000 61.625000 61.500000 61.532500 63.165000 67.142857 71.333333
    Pasta (P16) 217.500000 217.500000 182.525000 185.000000 165.000000 160.000000 175.000000
    Nuts (P17) 18.000000 32.000000 20.655000 21.265000 18.250000 11.250000 25.500000
    Chips (P18) 28.000000 24.333333 27.000000 26.000000 20.000000 18.000000 14.000000

    Table 3a. Median Portion Size (Pk) in Pyramid Servings* per Mention by Gender and Age for Fruits and Vegetables Analyses
    Food Group Age Group
    18-27 28-37 38-47 48-57 58-67 68-77 78-99
    Men
    100% fruit juice (P1) 2.000000 1.667500 1.335000 1.335000 1.334000 1.001000 1.001000
    Fruit (P2) 1.301000 1.301000 1.229571 1.227333 1.168000 1.168000 1.052333
    Salad (P3) 0.545000 0.708000 0.754500 0.750000 0.833500 0.750000 0.822500
    Fried potatoes (P4) 2.000000 2.000000 1.773000 1.710000 1.400000 1.250000 1.250000
    Other white potatoes (P5) 2.000000 2.000000 1.999000 1.999000 1.914000 1.544000 1.508000
    Dried beans (P6) 1.374000 1.047000 1.065000 1.227000 1.000000 1.000000 1.114000
    Other vegetables (P7) 0.750000 0.906000 0.974500 1.000000 1.000000 0.880000 0.833333
    Women
    100% fruit juice (P1) 1.500500 1.334000 1.334000 1.251250 1.019500 1.000500 1.000500
    Fruit (P2) 1.168000 1.168000 1.168000 1.168000 1.150500 1.083833 1.000000
    Salad (P3) 0.613500 0.572500 0.833333 1.000000 0.795500 0.625000 0.750000
    Fried potatoes (P4) 1.481000 1.365500 1.272000 1.400000 1.000000 1.026000 1.000000
    Other white potatoes (P5) 1.544000 1.544000 1.528000 1.544000 1.499000 1.516000 1.272000
    Dried beans (P6) 0.964000 0.684000 0.800000 0.687000 0.822000 0.807000 1.000000
    Other vegetables (P7) 0.702200 0.779333 0.792500 0.788500 0.774000 0.833000 0.856750

    * Defined by Dietary Guidelines Food Guide Pyramid (1992-2004).

    Table 3b. Median Portion Size (Pk) in Cup Servings** per Mention by Gender and Age for Fruits and Vegetables Analyses
    Food Group Age Group
    18-27 28-37 38-47 48-57 58-67 68-77 78-99
    Men
    100% fruit juice (P1) 1.499160 1.250580 1.000980 1.000980 1.000176 0.750735 0.750735
    Fruit (P2) 0.999580 0.933450 0.867300 0.867300 0.867300 0.774916 0.657060
    Salad (P3) 0.272700 0.353970 0.377235 0.374963 0.416640 0.375000 0.411323
    Fried potatoes (P4) 0.721125 0.727700 0.641000 0.641000 0.548055 0.480750 0.499980
    Other potatoes (P5) 1.000400 1.140030 0.999600 0.999600 0.999490 0.833175 0.754400
    Dried beans (P6) 0.717550 0.551540 0.566720 0.612360 0.500250 0.502285 0.575360
    Other Vegetables (P7) 0.387675 0.473920 0.499840 0.500240 0.499905 0.460585 0.416899
    Women
    100% fruit juice (P1) 1.124370 1.000960 1.000176 0.938130 0.764776 0.750728 0.750434
    Fruit (P2) 0.749235 0.867300 0.844838 0.789970 0.742350 0.712640 0.620475
    Salad (P3) 0.306788 0.286335 0.416625 0.499950 0.397688 0.312469 0.374963
    Fried potatoes (P4) 0.509595 0.455110 0.448700 0.448700 0.394856 0.444260 0.444260
    Other white potatoes (P5) 0.782020 0.876945 0.771260 0.771260 0.749700 0.771260 0.644235
    Dried beans (P6) 0.492150 0.341550 0.430530 0.345763 0.430685 0.430530 0.500400
    Other Vegetables (P7) 0.364468 0.395882 0.404303 0.408330 0.416913 0.436560 0.452214

    ** Defined by Dietary Guidelines for Americans, 2005: MyPyramid (2005).

  3. For percentage energy from fat and fiber (grams), estimation of bk, k = 0, ..., 19: the values for each parameter, for each gender, are in the following table:
    Table 4. Estimated Regression Coefficients for Foods as Predictors of Percentage Energy from Fat and Grams of Fiber, by Gender
    Parameter Men Women
    Percentage Energy from Fat Fiber (cube root) Percentage Energy from Fat Fiber (cube root)
    Intercept (b0) 31.93268 2.08423 31.36357 1.89847
    Cold cereals (b1) -0.02672 0.00209 -0.05797 0.00389
    Whole milk (b2) 0.00653 0.00013 0.00842 0.00009
    2% milk (b3) 0.00215 0.00013 0.00272 0.00011
    1% milk (b4) -0.00149 0.00022 -0.00196 0.00024
    Skim milk (b5) -0.00841 0.00028 -0.00867 0.00034
    Bacon or sausage (b6) 0.13831 -0.00139 0.23128 -0.00201
    Hotdogs (b7) 0.04078 0 0.10160 -0.00141
    Whole grain bread (b8) 0 0.00283 0 0.00337
    100% fruit juice (b9) -0.00533 0.00019 -0.01011 0.00025
    Fruit (b10) -0.00932 0.00103 -0.01201 0.00105
    Salad dressing (b11) 0.15036 0 0.23974 0
    Fried potatoes (b12) 0.02734 0.00160 0.04272 0.00156
    Other white potatoes (b13) 0.00580 0.00071 0.00618 0.00066
    Dried beans (b14) -0.00526 0.00275 -0.00608 0.00380
    Other vegetables (b15) 0 0.00084 0 0.00093
    Pasta (b16) -0.00504 0.00075 -0.00540 0.00082
    Nuts (b17) 0.12454 0.00546 0.26018 0.00603
    Chips (b18) 0.05376 0.00528 0.13144 0.00456
  4. For Pyramid servings of total fruits and vegetables, estimation of b0 and b1:

    The model is: E([Fruits and Veg]1/2) = b0 + b1 ([NFG1P1 + NFG2P2 + … + NFG7P7]1/2)

    For Pyramid servings of fruits and vegetables without French fries, estimation of b0 and b1:

    The model is: E([F&V not FF]1/2) = b0 + b1 ([NFG1P1 + NFG2P2 + … + NFG7P7]1/2)

    For Pyramid servings of fruits and vegetables, including and excluding French fries, for each gender, the estimates of the parameters are:

    Table 5. Estimated Regression Coefficients for Sum of Foods Predicting Pyramid Servings of Total Fruits and Vegetables and Fruits and Vegetables Excluding French Fries, by Gender
    Parameter Men Women
    Summary variable with French fries
    Intercept (b0) 0.906793 0.819559
    b1 0.758560 0.730865
    Summary variable excluding French fries
    Intercept (b0) 0.940772 0.816265
    b1 0.739056 0.730219

    For cups of fruits and vegetables (2005 MyPyramid definition), including and excluding French fries, for each gender, the estimates of the parameters are:

    Table 6. Estimated Regression Coefficients for Sum of Foods Predicting Cups of Total Fruits and Vegetables and Fruits and Vegetables Excluding French Fries, by Gender
    Parameter Men Women
    Summary Variable with French fries
    Intercept (b0) 0.666228 0.611844
    b1 0.770652 0.733890
    Summary Variable excluding French fries
    Intercept (b0) 0.706696 0.616033
    b1 0.742255 0.727761

Download the SAS program to compute the variables.

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Last Modified: 11 Apr 2014