This report from Harvard Business School finds that as employers continue to encounter major skills shortages, many qualified and willing workers remain unemployed or underemployed. These "hidden workers", ignored by employers for a variety of reasons, represent a potential source of much-needed labour. It identifies six main categories of part-time hidden workers and examines the obstacles they must navigate in finding employment. Though each faces a distinct set of hurdles, the report finds that they broadly require two key forms of support from their employers: increased flexibility and robust communication.