Since each survey is designed slightly differently, care must be taken when comparing across different countries. Table 6 summarizes the comparability of the different indicators across the countries and the survey year for each country. In most cases, the two survey years have comparable data and it is possible to compare the evolution of the indicators within a country. The notable exception is Bolivia where slightly different data were collected in the two survey years and the comparison of adequate food or adequate care measures through time is not possible. Comparisons across countries are more difficult. There are two sets of countries which have similar information. The first is comprised of Cambodia and Zimbabwe and the second of Ethiopia and Nepal. If the fact that the first set collects information for under 24‐month olds and the second for under 36‐month olds is not a concern, then all the four countries can be compared.

Currently many household level surveys have information on aspects of environment and health but the information regarding food and care aspects of nutrition is less robust. Understanding the synergies from the adequacies and nutrition would benefit from more detailed data collection especially of food and care components. Information on food security is crucial in complementing food diversity and minimum acceptable diet components to construct a holistic adequate food measure. Information on the knowledge of the caregiver regarding best child care practices is missing in all the surveys that we reviewed.

Another important consideration is that currently most studies are cross‐sectional and with few questions regarding the timing of various actions or information on past conditions. The implication is that we can only assess the child’s current situation and not the child’s cumulative experience. The fact that a child meets the recommendations for his or her age at the time of the survey, does not imply that he or she has always met the age appropriate adequacy definitions. So for example in the majority of our studies, for a child that is a year old, it is not possible to know whether the child was exclusively breastfed until 6 months and received at least one complementary food at 6 to 8 months. Similarly it is not usually possible to know if vaccinations or vitamin A supplements were received at the recommended ages, since many families only report whether the child has received the vaccination or supplement but not the actual date. Some components, such as access to improved sanitation, most likely have not changed for the majority of children since their birth, but other behaviors, such as hand washing may be components that may have changed. The lack of past information potentially leads to inflated numbers of children identified as adequate in a particular component when in fact they have been inadequate for some span of time since birth.

Many of the underlying measures are dichotomous leading to binary adequacy measures. The challenge and limitation with binary measures is the underlying assumptions that need to be made regarding cut‐off values or conditions. Continuous adequacy measures would allow to measure the correlations between changes in the adequacy levels and nutritional outcomes and thus providing more detailed information on the relationships and synergies. However, it is not easy to envision the construction of meaningful continuous adequacy measures.

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