Mr Vijayakumar Kassi is correct to say that it is hard to have a decent standard of living with a take-home pay of $1,120 per month (Challenges with Progressive Wage Model in the security sector, June 15).

The figure is derived from a security officer's minimum basic wage of $1,400, as recommended in the Progressive Wage Model, after the Central Provident Fund deduction of 20 per cent.

But if this is true, why are there still close to 50,000 security officers in Singapore?

A look at the advertisements for security officers in the jobs section of the Straits Times Classifieds shows that some firms are offering, on average, around $2,400 per month gross salary for a 12-hour shift, up to six days a week.

This additional $1,000 above the minimum basic wage recommendation of $1,400 comes from overtime pay as well as incentives for good behaviour such as not being absent or late. So it is possible for a security officer to take home about $2,120 per month.

A security officer is also allowed to work part-time for another security agency on his day off without violating the limit of 72 overtime hours in a month.

With the 72-hour limit being enforced by the Ministry of Manpower in the security sector from this year, security officers have six days off every four weeks.

This means they could potentially earn another $600 a month, based on a rate of $100 per 12-hour shift for part-timers.

For those who do not mind taking the night shift, the gross salary of a security officer can exceed $3,000 per month.

This is attractive for many seniors who would rather spend their time as a security officer instead of staying at home.

You need to pass three basic modules before you can get a security officer's licence.

But compared with the cleaning and landscape sectors, a security officer's job is less physically taxing and not subject to a harsh external environment. In fact, the guard room is often air-conditioned.

In summary, as long as the demand for security officers exceeds supply, market forces will dictate that the take-home pay will rise to what is needed for a decent living standard in Singapore.

Liu Fook Thim