Dietary assessment and physical activity measurements toolkit


‘There is not, and probably never will be, a method that can estimate dietary intake without error’ (Ruithauser and Black, 2002). The same could be said for the assessment of physical activity. Thus dietary and physical activity data require independent validation and the development of methods to assess the error structure to enable correction in data analysis. There are several sources of measurement error which may arise during the assessment of diet or physical activity. These errors will either be systematic or random.

The precision of dietary or physical activity measurement can be assessed and accounted for when determining sample sizes or analysing results. Random inaccuracy may lead to false negative conclusions in epidemiological studies by reducing true associations but will not generate misleading correlations. Non-random errors, or bias, are considered a more serious problem. 

Rutishauser IHE and Black AE, 2002
Measuring food intake. In Gibney, MJ, Vorster HH and Kok FJ (Ed.), Introduction to Human Nutrition First ed. (pp. 225-248) Oxford: Blackwell Science.

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