iso-strain. Effort-reward imbalance model The effort-reward imbalance (ERI) model focuses on the relationship between the worker's efforts and the work-related rewards the employee receives. The ERI model suggests that work marked by high levels of effort and low rewards leads to strain (e.g., psychological symptoms, physical health problems). The rewards of the job can be tangible like pay or intangible like appreciation and fair treatment. Another facet of the model is that overcommitment to the job can fuel imbalance. Person–environment fit model The person–environment fit model underlines the match between a person and his/her work environment. The closeness of the match influences the individual's health. For healthy working conditions, it is necessary that employees' attitudes, skills, abilities, and resources match the demands of their job. The greater the gap or misfit (either subjective or objective) between the person and his/her work environment, the greater the strain. Strains can include mental and physical health problems. Misfit can also lead to lower productivity and other work problems. The P–E fit model was popular in the 1970s and the early 1980s; however, since the late 1980s interest in the model has waned because of difficulties representing P–E discrepancies mathematically and statistical models linking P–E fit to strain have been problematic. Job characteristics model The job characteristics model focuses on factors such as skill variety, task identity, task significance, autonomy, and feedback. These job factors are thought to psychological states such as a sense of meaningfulness and knowledge acquisition. The theory holds that positive or negative job characteristics give rise to a number of cognitive and behavioral outcomes such as extent of worker motivation, satisfaction, and absenteeism. Hackman and Oldham (1980) developed the Job Diagnostic Survey to assess these job characteristics and help organizational leaders make decisions regarding job redesign. Diathesis-stress model The diathesis–stress model looks the individual's susceptibility to stressful life experiences, i.e., the diathesis. Individuals differ on that diathesis or vulnerability. The model suggests that the individual's diathesis is part of the context in which he or she encounters job stressors at various levels of intensity. If the individual has a very high tolerance (is relatively invulnerable), an intense stressor may not lead to a mental or physical problem. However, if the stressor (e.g., high workload, difficult coworker relationship) outstrips the individual's diathesis, then health problems may ensue. Job demands-resources model In the job demands-resources model model derives from both conservation of