Traditional and Rank-Based Tests for Ordered Alternatives in a Cluster Correlated Model

Psychometrika - Methods for the analysis of one-factor randomized groups designs with ordered treatments are well established, but they do not apply in the case of more complex experiments. This...     

Randomized controlled trial of an intervention to prevent adherence failure among HIV-infected patients initiating antiretroviral therapy.

OBJECTIVE: Compare the efficacy of a multicomponent social support intervention to standard-of-care counseling on medication adherence among HIV-infected patients initiating antiretroviral therapy. DESIGN: Randomized controlled trial. Generalized estimating equations tested for differences in the percentage of participants achieving 90% adherence. MAIN OUTCOME MEASURES: Pill-taking, electronically monitored over 6 consecutive months; plasma viral load (VL), assessed at 3 and 6 months following initiation of therapy. RESULTS: Of 226 participants who were randomized and began the trial, 87 (38%) were lost to the study by 6 months. The proportion of adherent participants declined steadily over time, with no time by group interaction. Sustained adherence was associated with increased odds of achieving an undetectable VL (OR=1.78; 95% CI=1.01, 3.13). In intention-to-treat analyses, a larger proportion of the intervention group than the control group was adherent (40.15% vs. 27.59%, p=.02) and achieved an undetectable VL p=.04). However, the majority of participants who remained on study experienced some reduction in VL (>or=1-log drop or undetectable), regardless of experimental condition. CONCLUSION: The multicomponent social support intervention significantly improved medication adherence over standard-of-care counseling; evidence for improved virologic outcomes was inconsistent. Early discontinuation of care and treatment may be a greater threat to the health of HIV patients than imperfect medication-taking.     

Attitudes and Attraction: Optimism and Weight as Explanations for the Similarity–Dissimilarity Asymmetry

The positive link between attitude similarity and attraction is one of the fundamental outcomes in social psychology. However, attitude dissimilarity seems to be a stronger driver of this relationship than attitude similarity. The authors review the evidence on this similarity–dissimilarity asymmetry, and discuss two explanations. One is that people generally enter into interactions with optimism, and so supposedly neutral partners are often seen as mildly positive. Another is that dissimilar attitudes carry greater weight than similar attitudes in cognitive processes. Implications of these mechanisms for wider issues in person perception and attitude structure are discussed, connecting them with more recent theories of attitudinal ambivalence and evaluative space.