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Multifactor Screener: 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 + ... + b20NFG20P20

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 20 food groups. These 20 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, ..., 20 on CSFII 94-96 adults aged 18 and above, stratifying by gender and excluding extreme exposure values. We first included all 20 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 Veg1/2) = 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

After exclusion of extreme and missing values, we performed the following steps with the Cancer Control Supplement dietary data to estimate the individual's intake of servings of fruits and vegetables, percent energy from fat, and fiber.

  1. Estimation of NFGk: All reported frequencies were standardized to a common unit of time by converting them to daily frequencies.

    Time Period Reported NFGk: Daily Frequency
    Day As reported
    Week Reported frequency divided by 7
    Month Reported frequency divided by 30
    Year Reported frequency divided by 365

  2. Estimation of Pk: The median age- and gender-specific portion sizes for each food were estimated from CSFII 94-96. For percent 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, 1/2 cup of other vegetables, or 3/4 cup vegetable juice; and
    • fruit: 1 whole fruit, 1/2 cup of cut-up fruit, or 3/4 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
    Other milk (P6)
    163.340000
    163.340000
    163.340000
    163.340000
    163.340000
    163.340000
    163.340000
    Bacon or sausage (P7)
    25.000000
    40.250000
    32.000000
    32.000000
    27.000000
    26.000000
    24.000000
    Hotdogs (P8)
    114.000000
    85.500000
    88.000000
    114.000000
    57.000000
    57.000000
    57.000000
    Whole grain bread (P9)
    56.000000
    54.000000
    52.000000
    52.000000
    51.000000
    48.250000
    48.000000
    100% fruit juice (P10)
    372.000000
    311.250000
    249.000000
    249.000000
    248.000000
    186.750000
    186.750000
    Fruit (P11)
    131.750000
    128.000000
    123.200000
    127.500000
    122.000000
    118.000000
    114.250000
    Salad dressing (P12)
    23.543333
    23.626667
    22.030000
    27.500000
    24.585000
    19.285000
    15.600000
    Fried potatoes (P13)
    112.500000
    114.000000
    100.000000
    100.000000
    85.500000
    85.500000
    97.000000
    Other white potatoes (P14)
    210.000000
    196.000000
    184.000000
    161.000000
    145.000000
    127.000000
    107.000000
    Dried beans (P15)
    180.000000
    130.000000
    172.000000
    172.000000
    158.125000
    175.000000
    170.100000
    Other vegetables (P16)
    60.013333
    73.000000
    74.063333
    79.833333
    76.500000
    73.000000
    67.520909
    Pasta (P17)
    330.000000
    280.000000
    280.000000
    247.500000
    280.000000
    210.000000
    210.00000
    Nuts (P18)
    31.625000
    58.000000
    35.500000
    54.665000
    39.250000
    17.130000
    35.916667
    Chips (P19)
    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
    Other milk (P6) 61.000000 61.000000 61.000000 61.000000 61.000000 61.000000 61.000000
    Bacon or sausage (P7) 26.000000 25.000000 24.000000 24.000000 18.000000 19.500000 16.000000
    Hotdogs (P8) 57.000000 57.000000 57.000000 114.000000 57.000000 57.000000 57.000000
    Whole grain bread (P9) 50.000000 48.000000 47.500000 45.000000 45.000000 42.400000 34.000000
    100% fruit juice (P10) 280.125000 249.000000 248.800000 233.250000 189.755000 186.600000 186.700000
    Fruit (P11) 118.000000 118.000000 118.000000 118.000000 118.000000 112.427143 109.000000
    Salad dressing (P12) 17.140000 20.626667 23.020000 21.873333 22.035000 18.335000 10.210000
    Fried potatoes (P13) 79.500000 70.000000 70.000000 70.000000 66.000000 70.000000 64.000000
    Other white potatoes (P14) 122.000000 127.000000 116.000000 122.000000 105.000000 105.000000 105.000000
    Dried beans (P15) 126.500000 89.000000 126.500000 126.500000 126.500000 126.500000 173.000000
    Other vegetables (P16) 53.750000 61.625000 61.500000 61.532500 63.165000 67.142857 71.333333
    Pasta (P17) 217.500000 217.500000 182.525000 185.000000 165.000000 160.000000 175.000000
    Nuts (P18) 18.000000 32.000000 20.655000 21.265000 18.250000 11.250000 25.500000
    Chips (P19) 28.000000 24.333333 27.000000 26.000000 20.000000 18.000000 14.000000

    Table 3.
    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

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

  4. 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) 31.952688 2.083624 31.371597 1.898219
    Cold cereals (b1) -0.025863 0.002045 -0.057206 0.003843
    Whole milk (b2) 0.006512 0.000129 0.008364 0.000095
    2% milk (b3) 0.002045 0.000137 0.002634 0.000115
    1% milk (b4) -0.001500 0.000225 -0.002082 0.000245
    Skim milk (b5) -0.008536 0.000285 -0.008775 0.000344
    Other milk (b6) -0.026527 0.001474 -0.047247 0.003496
    Bacon or sausage (b7) 0.138079 -0.001377 0.231718 -0.002043
    Hotdogs (b8) 0.041135 0 0.101657 -0.001416
    Whole grain bread (b9) 0 0.002827 0 0.003373
    100% fruit juice (b10) -0.005354 0.000187 -0.010099 0.000246
    Fruit (b11) -0.009290 0.001031 -0.011894 0.001046
    Salad dressing (b12) 0.149646 0 0.238928 0
    Fried potatoes (b13) 0.027202 0.001603 0.042656 0.001563
    Other white potatoes (b14) 0.005688 0.000716 0.006148 0.000658
    Dried beans (b15) -0.005231 0.002748 -0.005934 0.003787
    Other vegetables (b16) 0 0.000839 0 0.000932
    Pasta (b17) -0.005029 0.000753 -0.005416 0.000826
    Nuts (b18) 0.125658 0.005401 0.260003 0.006053
    Chips (b19) 0.053905 0.005276 0.130953 0.004592

  5. For Pyramid servings of fruits and vegetables, estimation of b0 and b1:
    The model is: E(Dietary Factor1/2) = 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

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Last Modified: 11 Apr 2014