CONCLUSION 3-3: Measures of acculturation and proxies such as language use, place of birth, and generation and time in the United States should, where feasible, be obtained.
We noted earlier that race and ethnicity are fluid concepts. While the meanings of race and ethnicity change over time, the relationship between race and ethnicity and SEP and acculturation may also change over time. For example, if patterns of immigration change (i.e., new groups from new areas immigrate to the United States and groups that have immigrated continue to assimilate), the existence and nature of disparities may also change. It is also possible that the economic and social positions of minority groups may change. Thus, how race and ethnicity are measured and the relationship of these two concepts to social and economic position and acculturation are likely to be reconsidered from time to time.
Some measurement issues are common to the collection of data on race, ethnicity, SEP, and acculturation and language use. Survey and administrative data systems are often limited in the amount of data that can be collected on each of these dimensions. As indicated earlier, sample sizes also limit statistically reliable estimation of disparities in health and health care within small population subgroups. In addition, health data are collected for several different purposes. Some data are collected to administer a program; for example, the primary use of Medicare claims data is to process payments for services. Data collected in the application process for health insurance are used to underwrite policies. Data on race and ethnicity are sometimes used to enforce civil rights laws. Because many of these data sets are not collected for research purposes, they may not have all the characteristics of an ideal data set for research on disparities in health and health care. Confidentiality and privacy issues may also limit their use because individuals who provided the data may not have been informed or have consented to let their data be used for purposes other than the primary reason the information was collected. Finally, because no one database is fully comprehensive for measuring race, ethnicity, SEP, and language use and acculturation, data linkages are often necessary to avoid the cost of new collections. The linkages can be difficult to arrange and come with their own privacy and confidentiality problems. This section discusses some of these problems in the collection of data on race and ethnicity, SEP, and language use and acculturation.