Organization of the United Nations, World Health Organization, and United Nations University (FAO/WHO/UNU, 1985) on energy and protein requirements discussed the procedure for estimating the variance that should be attached to the household energy requirement estimate. In theory, a probability statement can be made about the likelihood of adequacy of the household energy intake. However, because of the expected correlation between energy intake and energy need, it will be difficult or impossible to interpret the probability unless the observed household intake falls well above or well below the distribution of needs of similar households. When this occurs there are serious limitations to the assessment of the estimated energy intake of a particular household and attempts to do so (with currently available methodology) are not recommended.
When the intended application is to assess the apparent adequacy of a population of households (e.g., in the examination of data from a household food use survey involving a large number of households), one can estimate the mean household energy requirement as a demographically weighted average—the summation of requirements for the typical household. In comparison with the description above, the variance of requirement would be increased to allow for the variation in household composition. A major distinction between assessing a particular household and assessing a population of households is that the population average household intake should be expected to approximate the population mean household energy requirement, thus the confidence associated with an assessment of the total group should be improved. Conversely, because of expected correlation between energy intakes and energy needs at the household level, it is not possible to generate an unbiased estimate of the prevalence of inadequate intakes. The issues are the same as those for assessment of populations of individuals.
Assessing the adequacy of intakes of other nutrients at the household level is also possible but the process is more complicated than for energy. Unlike for energy, where an aggregate household requirement can be generated, an aggregate household requirement cannot be used as an EAR for other nutrients because intake and requirement are not correlated for most nutrients. Even if household intake appears to meet the aggregate household need for the nutrient, the lack of correlation between intake and need suggests that there is no assurance that nutrient intakes will be distributed within the