To determine if the American Academy of Pediatrics Attention-Deficit/Hyperactivity Disorder (ADHD) guidelines require tailoring for different settings, the researchers used a mixed-method research design to review an ADHD quality improvement effort in community clinics and private offices in San Diego County. Clinically, no differences were noted in rates of ADHD in the two settings. Children in community clinics (58.3%) were more likely to report public insurance (p<.001), diverse ethnic backgrounds (p=.003), low household incomes (p<.001), single parent households (p=.009), and to screen positive for Oppositional Defiant Disorder/Conduct Disorder (p=.027). They were also more likely to have experienced socio-environmental stressors (p<.001) including foster care, homelessness, parental drug use, and domestic violence. No differences were noted by treatment received at 12 months post-evaluation by office type. Open-ended interviews with clinicians confirmed these findings and revealed a need for tailoring of implementation strategies to more closely fit the needs of children and families cared for in public sector settings.