The authors use de-identified data from California personal income tax returns to measure the frequency and nature of independent contracting and self-employment in California. They identify this work by the presence of a Schedule C on the tax return and/or the receipt of a Form 1099 information return. The authors estimate that 14.4% of California workers aged 18 to 64 in tax year 2016 had some independent contracting or self-employment income and approximately half of this subgroup also had earnings from traditional W-2 jobs during the year. Only a small share (1.4%) of workers had earnings from online labor platforms (often called gig work). Workers with low earnings were significantly more likely to earn independent contracting or self-employment income and to rely primarily or exclusively on that income. The article explores the characteristics of workers engaging in independent contracting and self-employment and their distribution across family type, geography, and industry.This work has been supported, in part, by the University of California Multicampus Research Programs and Initiatives grants MRP-19-600774 and M21PR327
