Psychoanalysis has been slow in responding with formal research to challenges to the validity of its diverse and sometimes competing theoretical constructs. Among many psychoanalysts there is continued uncertainty about whether experimental and quantitative studies can contribute significantly to psychoanalytic knowledge, and resistance to introducing research procedures into analytic treatment. The methods and findings of a Berkeley research program are summarized, and implications for psychoanalytic theory and practice are drawn. A model for single-case quantitative research is described that uses information derived from the analyst-analysand interaction over the course of an analysis, and offers the potential for planned, systematic research through the replication of findings over a succession of analytic cases.