|A significant experience in workplace learning is the socialization of organizational newcomers. Public organizational leaders who fail to assess the content that newcomers learn during socialization may experience individuals negatively adapting to the organizational culture. This quantitative, cross-sectional research design involved a sample of 61 civilian newcomers employed with the United States Army Reserve (USAR). The study examined the relationships and predictive nature of mastery of socialization content (MSC) to organizational commitment (OC) and organizational citizenship behavior (OCB) among organizational newcomers. The Pearson correlation coefficient analysis was significant, r (61) =.458, p <.01 between MSC and OC. It was also significant, r (61) = .506, p < .01, between MSC and OCB. The politics socialization content area was significantly related to OC overall, R2 = .14, adjusted R2= .11, F(1,58) = 7.747, p < .001. The goals and values socialization content area was significantly related to OC overall, R2 = .26, adjusted R2= .21, F(1,56) = 9.032, p < .001. The linear combination of the goals and values and people socialization content areas were significantly related to OC overall, R2 = .38, adjusted R2= .31, F(1,54) = 10.175, p < .001. The politics socialization content area was significantly related to OCB overall, R2 = .14, adjusted R2= .11, F(1,58) = 8.741, p < .001. The goals and values socialization content area was significantly related to OCB overall, R2 = .42, adjusted R2= .37, F(1,56) = 26.630, p < .001. After controlling for age, there was a significant effect, F(1, 25) = 6.74, p = .05, partial η2 = .21. Pay grade also had a significant effect when controlled, F(1, 25) = 7.73, p = .01. The N-BIAS wave technique provided evidence that non-response should not be considered a major threat to the validity of the findings for this study, t(59) - .50, p > .04 and t(59) = 1.559, p > .05. Future research
is recommended to use a qualitative component to seek in-depth information about the phenomenon of newcomer socialization. Additionally, quantitative studies with other types of organizations would be useful to extend the findings of this study.