Adapting an existing instrument instead of developing a new one has both advantages and disadvantages. A disadvantage of adaptation includes the risk of imposing conclusions based on concepts that exist in one culture but may not exist in the other. Despite the difficulties associated with using adapted instruments, this practice is important because it allows for greater generalizability and allows for investigation of differences among a growing diverse population. Once the test has been adapted, test equivalence must be determined. Functional equivalence refers to the role or function that behavior plays in different cultures.
Conceptual equivalence refers to the similarity in meaning attached to behavior or concepts.
Certain behaviors and concepts may have different meanings across cultures. Metric equivalence refers to the psychometric properties and indicates that the scales measure the same constructs in different cultures. Finally, linguistic equivalence refers to the actual translation process. Another issue that must be considered in cross-cultural assessment is test bias. The test user must ascertain that the test and the test items do not systematically discriminate against one cultural group or another.