Methodology: Marin Magazine conducted a 2018 survey that has resulted in this [415] Top Doctors list — top physicians practicing in San Francisco and Marin counties who received multiple independent recommendations from their peers. The list was rechecked again this year. The survey process started with a list of more than 3,600 licensed doctors across all specialties in both counties. All doctors on this list were both candidates and eligible voters in the peer-to-peer voting poll. Doctors were allowed to cast an unlimited number of votes across all specialties — they could vote for as many doctors as they wanted regardless of specific area of expertise — but they could only vote for the same doctor once.

Response rate was maximized by the following procedures: (a) a long field period of 12 weeks that was further extended to allow all doctors ample time to log in and vote for peers; (b) multiple channels of solicitations including both individual invitations and organizational outreach to maximize contact with all eligible voters; and (c) repeated invitations and reminders to doctors who did not respond to initial rounds of solicitations. At the close of the voting period, approximately 670 doctors with the highest vote counts were short-listed for the database. Each of these doctors received a statistically significant number of votes from peers based on established principles of sampling probabilities and power analysis. LinChiat Chang, Ph.D.