Well I'd say it depends largely on ur grades.
I'm a diploma grad as well (grad in 2013) and have been working in one of the local hospitals healthcare admin since 8 months ago and earning bout $1900 ++ per month only (the job's irrelevant to my course of study though). I applied for PR in Feb and got the approval in early May and have just completed my formalities a week ago. The whole process took me about ... 3 months?
Well because of my scant work experience (it's the very 1st job of my life) and I knew it'd be a huge disadvantage to my application so I actually provided them with my detailed education docs (certifications of academic & co-curricular achievements from sec to poly), those're my only leverage I guess.
And the thing is I'm leaving for Australia at the end of next month for my degree study as I got a scholarship offer from one of the uni in Aus and that'll require me to be away from Spore for the next 2 years. I'm wondering how would that affect my PR status? Has anybody had any experiences in this?
Well after all, everything comes with a price, don't they?
Hope it helps and best of luck to you.
