However, population data from states in which diseases were not notifiable or disease data were not available were excluded from rate calculations. The data reported in this summary are useful for analyzing disease trends and determining relative disease burdens. However, these data must be interpreted in light of reporting practices. Finally, factors such as changes in the case definitions for public health surveillance, the introduction of new diagnostic tests, or the discovery of new disease entities may cause changes in disease reporting that are independent of the true incidence of disease. Public health surveillance data are published for selected racial and ethnic population groups because these variables may be risk markers for certain notifiable diseases.
Risk markers can identify potential risk factors for investigation in future studies.
Data regarding race and ethnicity also can be useful for identifying groups to target for prevention efforts. However, caution must also be used when drawing conclusions from reported data relating to race and ethnicity. Among persons of certain races and ethnicities, there are likely to be differential patterns of access to health care, interest in seeking health care, and detection of disease that would lead to data that are not representative of disease incidence in these populations. In addition, not all data concerning race and ethnicity are collected uniformly for all diseases. Additionally, although the recommended standard for classifying a person s race or ethnicity is based on self-reporting, this procedure may not always be followed.