Lazarus and Folkman's transactional model of stress posits that stress results from an imbalance between the demands of an event and a person's resources to cope with those demands. A person appraises a potential stressor through primary appraisal, evaluating whether it poses a threat, harm, or challenge. They then engage in secondary appraisal to assess their coping options and resources to determine if they can effectively manage the potential stressor. The interaction between the person's appraisals and coping abilities determines the level of stress experienced.