This report studies the career advancement prospects of people entering middle-skill jobs through the analysis of nearly four million resumes of middle-skill jobseekers. It highlights the types of occupations that offer the strongest opportunities for financial stability and true economic advancement. The research finds that, contrary to conventional wisdom, different middle-skill jobs offer considerable differences in advancement potential and financial stability., Jobs for the Future (JFF) and Burning Glass developed a new way of classifying and comparing the advancement potential of middle-skill work called the Opportunity Framework. The framework identifies three categories of entry-level jobs that provide completely different levels of career potential: lifetime jobs, springboard jobs, and static jobs. The first part of the report sets up the framework by describing five years in the careers of the fictional characters created for the report. The next part discusses each type of job in the Opportunity Framework in depth (lifetime, springboard, and static) using the characters to illustrate the impact of education and training decisions on real people. It incorporates discussion of door-opening and career-advancing credentials, as well as the skills that lead to advancement. In the final section, the authors recommend how education and workforce development leaders and policymakers can improve career training to increase economic advancement in the US, especially for low-income people and others under-served by existing systems.