The sample includes individuals who reported being retired in the current survey but working as employees in the previous one. Involuntary retirement is defined as retirement preceded by poor health or disability (including poor mental health or stress); by a layoff, business closure, or ownership change; or by changes in working conditions or compensation. The share of workers who retired involuntarily would be higher if it included workers who retired for caregiving reasons, but the survey questions do not differentiate between workers who retired when faced with caregiving responsibilities and those retirees who simply wanted to spend more time with family. Workers are represented by a union if they are union members or if they are not members but report that they are covered by a union contract. Self-employed workers are assumed to not be unionized.