Guys,
From my understanding, the criteria for the HR calling u up for an interview are as follows:
1) It should be > 6 months since your last interview.
2) You should be below 32 years of age.
3) You should not be employed by / Bonded by SIA or any of its subsidaries.
4) Must meet the height and eye sight requirements.
5) Minimum diploma holder
Feel free to correct me or add on..