There are two main problems with this kind of research. The first involves potential cultural differences in the understanding of what happiness means. The second has to do with the selection of study subjects. The sample from each country should be representative of the entire population. For example, if the sample is too heavily weighted toward educated, urban dwellers—who are much more likely to take surveys than uneducated rural villagers—then the happiness ratings may not accurately depict that country’s population. Cross-cultural happiness researchers are aware of these problems, however, and try to account for them in their study design.