ffq_sum_scores
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ffq_sum_scores [2021/07/29 16:23] laura [Remarkts from WUR researchers] |
ffq_sum_scores [2021/07/29 16:29] simone |
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| - | * //Frequency of consumption:// it is assumed that a month includes 28 days (refernce periode is 4 weeks). The frequency 'one day per week' will therefore receive the value 0.14 (4/28) | + | * //Frequency of consumption:// it is assumed that a month includes 28 days (reference periode is 4 weeks). The frequency 'one day per week' will therefore receive the value 0.14 (4/28) |
| * //Food items eaten within a food group// are assigned a value according to the frequency of their consumption: never = 0, sometimes = 0.33, often = 0.67, always = 1. | * //Food items eaten within a food group// are assigned a value according to the frequency of their consumption: never = 0, sometimes = 0.33, often = 0.67, always = 1. | ||
| * //Contributions of every food item// to the total consumption within the food group are recalculated so that they add up to 1, in order to make them evenly distributed. | * //Contributions of every food item// to the total consumption within the food group are recalculated so that they add up to 1, in order to make them evenly distributed. | ||
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| The WUR researchers listed the following points of attention: | The WUR researchers listed the following points of attention: | ||
| * **Extreme values have not been corrected:** Answers given to general questions on the diet as included in each FFQ questionnaire may be used to explain extreme values, but they have not been used to correct for extreme values in any way. It is up to individual researchers to include or exclude participants with extreme values in their analyses. | * **Extreme values have not been corrected:** Answers given to general questions on the diet as included in each FFQ questionnaire may be used to explain extreme values, but they have not been used to correct for extreme values in any way. It is up to individual researchers to include or exclude participants with extreme values in their analyses. | ||
| - | * **Not all missing values are treated equally:** When __frequency of consumption__ is missing the whole question cannot be interpreted and data for this food are not included in the calculations of total nutrient intake. Resulting in the possibility of underestimation of total daily intake of some nutrients for this participants. When __the number of servings and/or the food items consumed__ are missing, standard answers are used for calculations (according to the Dutch National Food Consumption Survey 1998). Because these are standard answers established for the whole population, the consumption of the food in grams per day and the intake of certain nutrients may be over- or underestmiated. | + | * **Not all missing values are treated equally:** When __frequency of consumption__ is missing, the whole question cannot be interpreted and data for this food are not included in the calculations of total nutrient intake. Resulting in the possibility of underestimation of total daily intake of some nutrients for this participants. When __the number of servings and/or the food items consumed__ are missing, standard answers are used for calculations (according to the Dutch National Food Consumption Survey 1998). Because these are standard answers established for the whole population, the consumption of the food in grams per day and the intake of certain nutrients may be over- or underestmiated. |
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ffq_sum_scores.txt ยท Last modified: 2024/01/29 12:44 by laura
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