Advantages of Within Group Analysis of Race/Ethnicity

Transcription

1 Advantages of Within Group Analysis of Race/Ethnicity KEITH E. WHITFIELD, PH.D. VICE PROVOST FOR ACADEMIC AFFAIRS PROFESSOR OF PSYCHOLOGY AND NEUROSCIENCE RESEARCH PROFESSOR OF MEDICINE CO- DIRECTOR OF CENTER ON BIOBEHAVIORAL HEALTH DISPARITIES RESEARCH

2 Health Disparities Compared to Caucasians, African Americans experience higher rates of: Hypertension Diabetes Obesity Fatal stroke Heart disease death End-stage kidney disease African Americans have a lower life expectancy rate than the overall population years compared to an average of 76.5 years for all population groups.

3 Model of Individual Variability in Health Social Environment Individual s Causal Field Behavior/ Genetic Racial Discrimination Social Support Neighborhood Access to Medical Care Health Disparities Chronic Conditions Mental Health Status

4 What is the question?? How do we typically understand minority populations? Comparing the minority group to majority Comparisons are conducted in pursuit of understanding health in minorities But is that what is really learn from comparison research?

5 Between Group Comparisons Mean Differences Reasonable elementary step toward understanding group differences Variance Differences Underlying distribution Assess invariance between groups May need to covary other critical factors

6 RA0C1(1):RESPONDENT AGE RA0C1(1):RESPONDENT AGE Caucasians African Americans Composite of verbal IQ scores and items from the Short portable Mental Status Questionnaire from Americans Changing Lives Statistical analyses of homogeneity reveal significant difference in the patterns of variability between the groups.

7 Sample size- the power to detect differences The power to detect differences is perhaps one of the most formidable challenges in comparison research. Samples need to be more than just representative in size to the population from which they are drawn. The variances need to be equivalent and the sample size needs to be sufficient to detect differences. Over sampling so the groups are equivalent in size. The challenge typically involves getting sufficient numbers of ethnic minorities to participate.

8 The ratio of African Americans to Caucasians is 1 to 2

9 The ratio of African Americans to Caucasians is 1 to 4

10 The ratio of African Americans to Caucasians is 1 to 6

11 Measurement Issues and Error Precision is a measure of how close a parameter estimate is expected to be to the true value of the parameter (Rosenthal et al, 2000). Precision is then driven by the smaller of the groups. Scientists must assure that the instrument used to measure the construct of interest has the same meaning across groups including measurement error and equivalence across groups. Need measures that are not bias by cultural factors

12 Models of Cultural Differences (Cauce, Coronado & Watson, 1998) Cultural Deviance Model Differences or deviations between groups are seen as deviant and inferior. Cultural Equivalence Model Superior socioeconomic status has provided advantages. Deviant perspective attributed advantages to culture. Cultural Variant Model Resilience in the face of oppression Adaptation and survival due to external forces Culturally rooted, internal explanations for differences

13 Equivalence of Measures Cauce et al., 1998 Cultural Equivalence Extent the measure has same internal structure and meanings within and across groups Conceptual Equivalence Content of items is defined similarly across groups Items are equally familiar across groups

14 Equivalence of Measures (cont.) Linguistic Equivalence Language of items is understood the same across groups (e.g. Blue) Functional Equivalence Scores have similar correlates across groups Scalar Equivalence Scores reflect the same level of the construct across groups

15 Interpreting Results Differences can mean strengths Trajectories of change may be different the more assessment points the better Including a measure of ethnicity (e.g., acculturation) can be used to examine mediate or moderating effect between groups

16 Within-Group Individual Differences Strengths Understand variability in measure specific to group. Error of measurement limited to measure and not ethnicity Weakness Limited description of phenomena can be made description specific to minority group Should between group research be done? Which should come first between or within group studies?? Is there cases when within group analyses is not appropriate?

17 Genes and Health Disparities Prevalence of some risk genetic alleles may differ by race/ethnicity. Environmental context can differ markedly across all disparities populations Search for possible gene X environment interactions

18 Ways Interactions can happen Environmental Risk Factor Genotype Environmental Risk Factor Disease Genotype Disease Genotype Environmental Risk Factor Disease Genotype Genotype Environmental Risk Factor Disease Environmental Risk Factor Disease Ottman, R. (1996). Gene-Environment Interaction: Definition and study design, Preventive Medicine, 25,

19 Summary Studying minorities offers unique opportunities not yet fully appreciated by many researchers Understand how social and psychological factors impact health. Future research that accurately and appropriately utilizes minorities for understanding medical conditions will advance the field. Alternative strategies to studying minorities will help advance an understanding of minorities and all people. More than one way to skin a cat!