Employer practices such as hiring, scheduling, promotion, supervision, and on-the-job training determine workers’ day-to-day reality and long-term prospects in the labor market. The growing prevalence of independent contractors and contingent workers underscores the continued fissuring of employer-employee relationships. And the rise of the gig, app-based economy signals that more workers are pursuing nontraditional work arrangements, which may offer both advantages (flexibility and supplementary income) and disadvantages (income volatility and a lack of worker protections and access to benefits). WorkRise generates evidence on and elevates our understanding of how employer practices and shifting employer-employee relationships shape economic security and mobility.