A Quantitative Integration of the Military Cohesion Literature

Abstract

In this article, we review research on group cohesion in military units, using meta-analytic techniques that convert research findings to a common metric. After combining some of the 39 samples to eliminate possible overlap in participants, we conducted separate analyses for 7 different outcomes. Effect sizes (correlation coefficients), weighted by the number of participants, were .40 for cohesion and group performance, .20 for cohesion and individual performance, and .47 for cohesion and joblmilitary satisfaction. Cohesion was also positively related to measures of retention (.22), well-being (.24), and readiness (.30) and was inversely related to rates of indiscipline (-.14). although these latter results are not definitive because of the smaller number of samples involved. Effect sizes weighted by the number of groups generally tended to decrease the number of cases, increase the effect sizes, and broaden the confidence intervals. We conclude that group cohesion results in desirable outcomes for the military and that the research has implications for policy and training issues. We recommend that future cohesion researchers include all basic datain their research reports, delineate their concepts explicitly, use valid and reliable measures, and give careful consideration to the level of analysis and other moderator variables.

Notes

1 We did not include this study (Hoiberg & Pugh, 1978) in our meta-analysis because the cohesion measure was the respondent's expectations for cohesion at the respondent's next duty station. We felt that expectations did not meet our definition of cohesion, as we have interpreted the construct.

2 This procedure is in contrast to using the reciprocal of the sampling variance of r as recommended by Shadish and Haddock (1994) in their chapter on combining estimates of effect size. Some authorities believe using sample size is preferable to using the variance of r, although the former procedure is technically more approximate. B. J. Becker (personal communication, April 3, 1996) has found that, in practice, sample size works better. We found that using sample size resulted in more conservative (i.e., broader) estimates of confidence intervals.

3 We did not have enough cases for most outcomes to compare group- and individual-level analyses as Gully et al. (1995) did. However, we obtained an effect size of .439 for the 12 cases of group performance that used the group as the unit of analysis. The 4 cases of group performance that correlated individual cohesion measures directly with individual performance measures resulted in an effect size of .347.

4 Of these 4 studies, 2 included civilian as well as military personnel, 1 did not involve an ongoing group, and 1 lacked a measure that met our definition of cohesion.