Deciding which employee should perform which job, and when, is a recurring decision in manufacturing, logistics, healthcare, retail, education and professional services. Operations Research (OR) offers a family of models for this decision, ranging from the classical one-to-one assignment problem to large shift-scheduling and rostering formulations. This review analyses twenty-five studies, published between 2007 and 2026, that apply OR to employee–job assignment and workforce scheduling in real or realistic settings. The studies were screened against clearly defined inclusion criteria and grouped into four streams: classical assignment solved by the Hungarian method, competence- and preference-based assignment, integrated task scheduling and staff assignment, and workforce sizing and shift scheduling. For each study the problem scope, model structure, treatment of rules, skills, fairness and preferences, solution method and reported results are extracted and compared, and published results were re-computed independently where the data allowed.

Three worked examples illustrate the main model types: the Hungarian method reduces a courier assignment from 114 to 81 minutes (28.95%), a shift-covering model finds the minimum staff for a 24-hour roster, and a multi-criteria example shows that a published allocation can be improved by a simple swap of tasks. Every field which has a manual baseline reports improvement with such indicators as the reduction in time by 26–29%, reduction in payroll by approximately 10–20%, the increase in the proportion of satisfied tutor preferences from 31% to 60%, and the elimination of rule violations. Exact methods are applicable to only one-to-one cases and some reduced forms of rostering such as compact and decomposed ones while complex multi-day and multi-skill rostering as well as bilevel ones require heuristic approaches. The problems needing additional research are the use of only one organisation or data set to evaluate the performance, limited consideration of preference and uncertainty factors, and shortage of before-and-after studies.

Keywords— Assignment problem; Hungarian method; Workforce scheduling; Staff rostering; Integer programming; Operations research.