On what basis can employees ask for a higher pay?
They can ask for a raise by doing good work. This is true even if those employees have never been greedy or wanted a raise in the past, or if they have been denied raises in the past. A good basis is that they have been performing well, and the performance has been improving over time. Employees should show enthusiasm, be open to new ideas, be a positive influence on their coworkers, show a certain commitment to learning and another is that they've been improving their quantitative skills.