In recent years Congress and the Administration have taken actions to build a more diverse and representative military workforce. In the Duncan Hunter National Defense Authorization Act for Fiscal Year 2009 ( P.L. 110-417 ), Congress mandated the creation of a Military Leadership Diversity Commission (MLDC) tasked with conducting "a comprehensive evaluation and assessment of policies that provide opportunities for the promotion and advancement of minority members of the Armed Forces, including minority members who are senior officers." The commission's final report, From Representation to Inclusion: Diversity Leadership in the 21 st -Century Military , noted that while great strides had been made in developing a diverse force, women and racial/ethnic minorities are still underrepresented in top leadership positions. In May 2011, the commission's report was released, and in August 2011 President Barack Obama issued an Executive Order (EO 13583) calling for a coordinated government-wide initiative to promote diversity and inclusion in the federal workforce. In Section 528 of the National Defense Authorization Act for Fiscal Year 2016 ( P.L. 114-92 ), Congress reaffirmed a commitment to maintaining a diverse military stating: Diversity contributes to the strength of the Armed Forces.... It is the sense of Congress that the United States should—(1) continue to recognize and promote diversity in the Armed Forces; and (2) honor those from all diverse backgrounds and religious traditions who have made sacrifices in serving the United States through the Armed Forces. Military manpower requirements derive from National Military Strategy and are determined by the military services based on the workload required to deliver essential capabilities. The 2015 National Military Strategy highlights the importance of diversity in acquiring those capabilities, stating: To enhance our warfighting capability, we must attract, develop, and retain the right people at every echelon. Central to this effort is understanding how society is changing… Therefore, the U.S. military must be willing to embrace social and cultural change to better identify, cultivate, and reward such talent. In this regard, DOD's pursuit of a diversity management program is one means to broaden the potential pool of high-quality recruits and to retain those individuals who can best fill required roles at every level. DOD's definitions of diversity and equal opportunity have changed over time, as have its policies towards inclusion of various demographic groups in military service and occupational assignments. In some cases, these changes have come about in response to changes in law. Under Article 1, Section 8 of the U.S. Constitution, Congress has the authority to raise and support armies; provide and maintain a navy, and to provide for organizing, disciplining, and regulating them. In the past, Congress has used this authority to establish criteria and standards for recruiting individuals into the military, promoting them, and separating or retiring them from military service. Throughout the history of the armed services, Congress has established some of these criteria based on demographic characteristics such as race, sex, and sexual orientation. The gradual integration of different demographic groups into the military has continued since the 19 th century; however, in the past decade there have been rapid changes to laws and policies with regard to diversity, inclusion, and equal opportunity in the Armed Forces. Since 2009, DOD policy changes and congressional actions have allowed individuals who are gay to serve openly and recognized their same-sex spouses as dependents , opened all combat assignments to women , and, as of June 30, 2016, changed policies that restricted transgender troops from serving. Some feel that these changes are happening too quickly or should not happen at all citing potential negative impacts on military readiness and unit cohesion. Others argue that DOD's shifting policies reflect broader societal, cultural, and demographic shifts within the United States, and will create a stronger, more effective force. This report starts by giving an overview of recent research on diversity and organizational management to demonstrate why organizations value diversity and what the findings on diversity mean in a military context. The next sections outline DOD's military personnel policies, processes and organizational structure for managing diversity, inclusion, and equal opportunity. Following that, the report examines how the concept of diversity and inclusion has evolved over the history of the Armed Forces and provides a snapshot of the current demographic composition of the military relative to the U.S. civilian population. Finally, the report addresses some of the current legislative and policy issues related to diversity in the Armed Forces. Diversity is often defined as the variation of traits within groups of two or more people and may include both visible (e.g., sex, age, race) and invisible (e.g., knowledge, culture, values) traits. An Internet search on "diversity initiatives in the workplace," produces more than 1 million results. Given the emphasis placed on diversity by modern organizations it is important to understand why workforce diversity is valued and what that means in the context of military personnel management. Many argue that diversity is a core value of an egalitarian and multicultural society and organizations should seek diversity regardless of its relationship with performance metrics. From a human resource perspective, diversity is typically studied with regard to its impact on group dynamics and other factors that contribute to organizational performance. Two key factors that have been studied in both the civilian and military context are cohesion: commitment to other members of the group and the group's shared objectives; and effectiveness: the ability of the group to efficiently meet its objectives. Studies on the impact of diversity on these factors have had mixed findings, leading some to argue that diversity is beneficial to organizational success, and others to suggest that it might be harmful. There are varying definitions of cohesion. In the military context, the 1992 Presidential Commission on the Assignment of Women in the Armed Forces defined it as the relationship that develops in a unit or group where (1) members share common values and experiences; (2) individuals in the groups conform to group norms and behavior in order to ensure group survival and goals; (3) members lose their personal identity in favor of a group identity; (4) members focus on group activities and goals; (5) unit members become totally dependent upon each other for the completion of their mission and survival; and (6) group members meet all standards of performance and behavior in order not to threaten group survival. In this regard, military cohesion is often considered to be a positive group attribute that contributes to the team's ability to cooperate and perform at high levels under stressful conditions. Some studies have found that higher overall levels of cohesion are associated with individual benefits of increased job satisfaction, retention, and better discipline outcomes. Meta-analysis of group performance and cohesiveness has suggested that, on average, cohesive groups perform better than non-cohesive groups. Others note that where observed causal relationships between cohesion and group performance exists, it is more often the performance of the group that affects the level of cohesiveness (i.e., unit success leads to a more cohesive unit) rather than the opposite. Recent studies of group cohesion focus on two ways that group cohesion develops. Social cohesion is the extent to which group members like each other, prefer to spend their social time together, enjoy each other's company, and feel emotionally close to one another. Task cohesion is the shared commitment among members to achieving a goal that requires the collective efforts of a group. Some behavioral research has found that interpersonal relationships that lead to social cohesion are established more readily between individuals with similar backgrounds, experiences and demographic characteristics. In addition, some studies have found that teams with high levels of social cohesion have less conflict and stronger support networks that may help individuals to better cope with stress. In the military context, those who argue for more homogenous units argue that these units develop stronger interpersonal bonds which provide important psychological benefits and bolster unit resiliency when operating in highly stressful and austere environments. They also argue that "out-group" members—those with different characteristics than the majority of others in the groups—may experience negative individual psychological effects as a result of poor social integration. Other studies have found shared experiences can contribute to task cohesion and that this type of cohesion is a stronger predictor of group performance than social cohesion. This leads some to argue that the "sameness" of individuals in a military unit is less important than the shared experiences of the unit. In this regard, some argue that military units that operate in an integrated manner can build task cohesion through integrated training. Some studies on the effectiveness of small groups have found that the presence of diversity (in particular racial and gender diversity) is associated with better creative problem solving, innovation, and improved decisionmaking. These positive outcomes are sometimes attributed to the broader range of unique perspectives, knowledge, and experience available in diverse groups relative to homogenous groups. In this regard, those who argue for diversity initiatives in the military argue that a more diverse force has the potential to be more efficient and flexible, able to meet a broader set of challenges. Other studies have found that within diverse groups individuals with demographically similar characteristics tend to build strong in-group relationships to the detriment of the larger unit. The presence of demographic "in-groups" has been found in some circumstances to negatively affect group productivity, particularly if active "fault lines" or biases exist between subgroups. Those who argue against the integration of certain subgroups suggest that there are pervasive cultural biases that contribute to interpersonal friction within military units and could distract from the unit's ability to perform under stress. While the direction and magnitude of effects of diversity on group performance remain debatable, there is a wide body of literature that links performance of diverse groups to leadership and management. Among human resource professionals in the public and private sectors, the focus in workforce management has shifted from diversity acquisition (e.g., affirmative action and hiring quotas) to diversity management. Under the previous philosophy, employers set targets for accessions based on race, sex, or other attributes in order to bolster historically under-represented groups. More recent diversity management philosophies focus on building organizational culture and policies to better attract a diverse workforce and to accommodate career development for employees with different backgrounds.