Aaron Belkin and his colleagues at the Palm Center conducted extensive interviews over the past six months with retired generals and admirals, anti-repeal activists, active-duty servicemembers, and watchdog organizations on both sides of the issue, in addition to analyzing the experience of several military units and media coverage. Here’s what the study [PDF] found about the impact of gay, lesbian, and bisexual troops serving openly:

• Repealing DADT has had no overall negative impact on military readiness, including cohesion, recruitment, retention, assaults, harassment, or morale.
• Greater openness and honesty post-repeal may have actually increased understanding, respect, and acceptance.
• Recruitment has remained robust.
  Retention was unaffected by repeal. Only two individuals’ departure can be tied to repeal, both military chaplains.
• There has been no increase in violence within units; in fact, many harassment disputes can now be resolved in ways that were not possible when servicemembers could not disclose their sexual orientation.
• Unit morale was not impacted, except on the individual level depending on a servicemember’s personal position on the issue of DADT.
• LGB servicemembers did not come out en masse.