In the latter half of this decade, the U.S. Army has been engaged in persistent asymmetric warfare. During this period, army organizations have varied in the degree to which they have innovated doctrinally and technologically to confront this new reality. At the broadest level, the army has innovated considerably. However, at the combat brigade level, we observe variation across medical and logistics units, critical for providing support for combat operations. This thesis explains this variation. Several authors propose that units learn and innovate primarily during wartime or peacetime, and they do so from either a top-down or bottom-up methodology. Yet, such methods of learning do not adequately explain variations between respective levels of innovation in which logistics forces within combat brigades have seemingly adapted more rapidly than their medical counterparts. This thesis suggests that another factor, organizational complexity, explains why the brigade support medical company has not adapted as rapidly as its logistics counterparts within the support battalion (BSB) structure.