Companies sometimes think that if not enough people with the right skills answer their job advertisement, the only response is to raise the salary. Low pay may be one reason but to assume it is the only reason is unwise and can be costly. Looking at the whole employment package is also important. You may be able to improve the attractiveness of the package by changing elements other than pay. It is not good practice to base your judgement on a few employees who have left for higher paid jobs, or on higher salaries seen in a few job advertisements.
All organisations experience some staff movement.
Employees may leave for other reasons but quote pay as the easiest explanation. Job titles in advertisements may be similar to yours, but the job content may be different. Surveys will show you the upper and lower limits of the pay range that different employers pay for the same or similar jobs. You may decide you need to be a market leader. Professional pay surveys usually include information about non-pay benefits such as pensions, holidays, sick pay and company cars.