I moved to the United States in 1981 on a Student Visa. I…

The Old Age Security pension is like a large pie divided into 40 equal portions. If you qualify for the "full pension," you are entitled to receive all 40 portions each month. If you qualify for a "partial pension," you will receive some, but not all, of the 40 portions each month. Whether you qualify for a full or partial pension depends on how long you've lived in Canada.

Full Pension

Normally, if you meet the conditions in either of the two categories below, you qualify for a full pension:

Category 1 -

• You lived in Canada for at least 40 years after turning 18.

Category 2 - You were 25 years of age or over on July 1, 1977, and;

1. resided in Canada, or;
2. had some prior residence in Canada after age 18, or;
3. were in possession of a valid Canadian Immigration Visa and

You resided in Canada for the 10 years immediately prior to the approval of your application.

If you have not lived in Canada for all of these last 10 years because you gave up residence here at some time, you may still qualify for a full pension if you meet both conditions below:

• You lived in Canada for the year immediately before your application was approved.
• Prior to these last 10 years, you lived in Canada after age 18 at least 3 times as long as the total of your absences during the last 10 years.

Partial Pension

If you don't qualify for the full pension you may qualify for a partial pension. Once a partial pension is approved, the number of portions of the "pie" that you will receive can never be increased. You will, however, qualify for any cost-of-living increases.

In terms of CPP that is based on your contributions that you made when working in Canada and not on residency.

Let me know if you need further clarification.