Burns T, Patrick D. Social functioning as an outcome measure in schizophrenia studies. Objective: Deficits in social functioning are a core feature of schizophrenia. Method: A literature search of English language articles published between January 1990 and December 2006 was undertaken to identify: i) scales used most frequently to assess social functioning in schizophrenia; and ii) the most frequently used social functioning scales in randomized, controlled trials of antipsychotics. A further search (without time limits) examined their psychometric properties. Results: A total of 301 articles employed social functioning scales in the assessment of schizophrenia. These contained 87 potentially relevant measures. Only 14 randomized, controlled studies of antipsychotic agents were identified that examined social functioning. Scales varied greatly in terms of measurement approach, number and types of domains covered and scoring systems. A striking lack of data on psychometric properties was observed. Conclusion: Limited consensus on the definition and measurement of social functioning exists. The Personal and Social Performance Scale is proposed as a useful tool in future research.