What is psychological well-being and how it changes throughout the employment cycle?

Nowadays, there is much evidence about the importance of psychological well-being in the workplace. Research has demonstrated consistently that employee’s well-being is positively associated with physical health and is a strong predictor of high individual work performance as well as of some outcomes at organisational level (e.g. customer satisfaction, productivity, profitability and employee turnover). Overall, it is known that employees with high levels of psychological well-being perform better at work than those with lower levels of psychological well-being. However, researchers do not always agree on what exactly well-being means and how it can be measured.