Over the past decade, the issue of measurement equivalence or cultural invariance in responses to the CES-D has been examined for several racial and ethnic groups (e.g., Cole et al., 2000
; Crockett et al., 2005
; Kim et al., 2009
). This attention has been prompted by the recognition that measurement equivalence is a fundamental issue in cross-cultural studies. Although limited by relatively small sample sizes and descriptive analytical strategies, a few studies have addressed cultural response bias in the CES-D in Asian populations (e.g., Iwata & Buka, 2002
; Y. Jang et al., 2005
; Young et al., 2002
). The availability of large data sets of non-Hispanic Whites, Korean Americans, and Koreans that used the 10-item CES-D enabled us to perform an advanced DIF analysis focusing on the role of culture. The present analysis was strengthened by the further exploration of subsamples of Korean American immigrants with varying levels of acculturation to mainstream American culture.
A series of DIF analyses using MIMIC models provided evidence that supported our hypotheses. Our results indicated that both Korean Americans and Koreans were less likely to endorse positive affect items compared with Whites, but at the same time, Korean Americans were more likely to endorse these items than those in the Korean sample. Similarly, within the Korean American sample, the same reduced likelihood of endorsing positively worded items was observed among the less acculturated subgroup compared with the more acculturated subgroup.
Given that measurement invariance is a prerequisite for a valid cross-group comparison, our findings on DIF suggest that researchers should be cautious about using simple mean comparisons and a universal cutoff point. In the presence of DIF, such approaches may lead to inaccurate prevalence estimation and invalid group comparisons (Crockett et al., 2005
). Previous studies have consistently reported relatively high levels of depressive symptoms in Korean populations (e.g., Y. Jang & Chiriboga, 2010
; Kuo, 1984
; Lee, Moon, & Knight, 2005
; cf. Mui et al., 2003
). Indeed, Korean Americans are often profiled as a high-risk group in mental health research because their rates of probable depression as indexed by standardized depression screening tools are up to four times greater than those of Whites or African Americans (Y. Jang & Chiriboga). Our findings suggest that the CES-D scores of Korean populations may be inflated because of their biased response patterns independent of mental health status. However, as shown in , our results also indicate that negative item total scores were also still relatively high for the Korean American sample. Similarly, Kim and colleagues (in press)
found that Korean Americans had the highest depressive affect scores among five ethnic groups of Asian Americans in the 2007 California Health Interview Survey where the K6 (Kessler et al., 2002
), an instrument that only includes items representing negative emotion, was employed.
Some limitations to the present study must be noted. The present comparative analyses used three data sets that were established as a result of independent research efforts. Therefore, some degree of discrepancy in study designs and measures is unavoidable. There were also procedural differences between the three methodologies (e.g., telephone survey/mail survey/in-person interview, 2- to 4-year differences in when the data were collected). Different mental status screening tools were used in the SOF and KLoSA, and there was no formal screening of the Korean American sample. Although the present study used the suggested cutoffs for the SPMSQ and Mini-Mental State Examination to exclude individuals with impairment in mental status, there is a lack of empirical evidence for the validity of these cutoffs in cross-cultural settings. The representativeness of the samples is another potential limitation. Although the KLoSA is a nationally representative sample and the SOF is a statewide probability sample of Florida, the Korean American sample was drawn from only two cities in Florida. Given this geographic restriction, the generalizability of the findings to whole populations may be limited. It should also be noted that we inferred differences in underlying cultural attributes across the groups in the absence of direct measures of cultural values (e.g., modesty, self-effacement). Future studies need to assess cultural values and their influence on response patterns. Because the current analysis was restricted to individuals aged 65 and older, future investigations should broaden the age range to include younger individuals and life-span perspectives. Given the fact that neither culture nor historical period is static, longitudinal and cohort sequential assessment will also provide a needed perspective.
Despite these limitations, our findings clearly show that the way in which people respond to the CES-D varies by cultural orientation. Given that most research on depressive symptoms relies on self-report inventories and that cultural orientations may systematically bias responses to such inventories, caution should be exercised in interpreting the results of this research, particularly in the context of cross-group comparisons. Regrettably, there is at present no standard approach to correcting for DIF, which calls attention to the urgent need for more research in this area.