# Diet Screener in the 2005 CHIS: Scoring Procedures

## How Analytical Scoring Procedures Were Developed

Scoring procedures were developed to convert the individual respondent's screener responses to estimates of individual dietary intake for servings of fruits and vegetables and teaspoons of added sugar using USDA's 1994-96 Continuing Survey of Food Intakes of Individuals (CSFII 94-96) dietary recall data.

For servings of fruits and vegetables:

E(Fruits and Veg1/2) = b0 + b1(NFG1P1 + NFG2P2 + ... + NFG7P7)1/2

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; k indexes the 7 fruit and vegetable food groups. Pk is the median portion size of group k. We calculated weighted least-squares estimates of the regression coefficients b0 and b1 on the adults (aged 18 and above) in the CSFII 94-96 sample, stratifying by gender and excluding extreme exposure values.

## Scoring Procedures

After excluding extreme and missing values, we performed the following steps with the CHIS dietary data to estimate the individual's intake of servings of fruits and vegetables.

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

For Fruit and Vegetable Intake:

1. Estimation of Pk: The median age- and gender-specific portion sizes for each food were estimated from CSFII 94-96. The units were in Pyramid servings (Table 1).

A Pyramid serving is defined by the U.S. Department of Agriculture in the 1992 Dietary Guidelines Food Guide Pyramid 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.

More recently, the 2005 Dietary Guidelines measure fruits and vegetables in cup equivalents. See MyPyramid for definitions of cup equivalents.

Both metrics are provided for these 2005 data.

Table 1a. 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
Table 1b. Median Portion Size (Pk) in Cup Equivalents** 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 white 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
2. 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 and dried beans, for each gender, the estimates of the parameters are:

Table 2a. Estimated Regression Coefficients for Sum of Foods Predicting Pyramid Servings* of Different Versions of Daily Servings of Fruits and Vegetables, 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
Summary Variable excluding French fries and beans
Intercept (b0) 0.950228 0.813568
b1 0.723395 0.723230
Summary Variable excluding beans
Intercept (b0) 0.884786 0.813994
b1 0.761347 0.726001
Table 2b. Estimated Regression Coefficients for Sum of Foods Predicting Different Versions of Daily Cup Equivalents of Fruits and Vegetables**, 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

Summary Variable excluding French fries and beans

Intercept (b0) 0.719659 0.618209
b1 0.723629 0.718681
Summary Variable excluding beans
Intercept (b0) 0.671443 0.613051
b1 0.758684 0.725692

1. Estimation of Pk: The median age- and gender-specific portion sizes in grams for each food were estimated from CSFII 94-96 (Table 3).
Table 3. Median Portion Size (Pk) in Teaspoons*** per Mention by Gender and Age for Added Sugar Analyses
Food Group Age Group
18-27 28-37 38-47 48-57 58-67 68-77 78+
Men
Regular soda (P1) 11.246397 9.221880 9.221880 9.221880 9.214440 9.125268 9.115360
Fruit drinks (P2) 10.600000 8.636250 8.565000 8.565000 6.276880 5.700512 5.540320
Cookies, cake, pie (P3) 5.083032 4.762847 4.582705 4.426306 4.552020 4.216712 3.761836
Ice cream (P4) 7.046725 5.905380 6.783700 5.858650 5.858650 4.759920 3.478629
Women
Regular soda (P1) 9.221880 9.221880 9.184695 9.125268 8.041256 7.684900 9.120314
Fruit drinks (P2) 8.246250 7.773757 6.276880 6.218740 6.251570 5.353125 5.300000
Cookies, cake, pie (P3) 3.945000 3.533487 3.649440 3.595380 3.866728 3.315540 3.027309
Ice cream (P4) 5.858650 5.546760 5.814600 4.933600 4.560570 3.920450 3.920450
2. For teaspoons of added sugar, estimation of b0 and b1:
The model is: E(Dietary Factor1/3) = b0 + b1 (NFG1P1 + NFG2P2 + ... + NFG4P4)1/3

For teaspoons of added sugar, estimates of the parameters are:

Table 4. Estimated Regression Coefficients for Sum of Foods Predicting Teaspoons of Added Sugar***, by Gender
Parameter Men Women
Intercept (b0) 1.566813 1.481876
b1 0.555082 0.514735

* Using 1992 Food Guide Pyramid definitions of servings.

** Using 2005 MyPyramid definitions of cups of fruits and vegetables.

*** Using 2005 MyPyramid database.