not random but justified statistical methods for validating a diet quality index

#1
Has anyone good advice for validating a diet quality index? I have gone through validation studies and the methods used vary a lot. Some of them do not seem reasonable to me and the reasoning for concluding the tool "valid" is often not based on anything. Or so it seems to me. My question is, what is a proper protocol for validating a diet quality index when validating against nutrient intake from diet records?
 

hlsmith

Omega Contributor
#2
You need to provide more information. Is a "diet quality index" a survey that provides a single number that represents the potential overall dietary quality of food that was taken in? Another big question is what do you compare this to? Typically you validate by comparing to a gold standard to see how good your proxy is at estimating the truth. Also, how is the gold standard quantified?