There's nothing I like more than a technical question.
The OECD follows an international norm, which is that to calculate the relative incomes of older people and the poverty rate we look at equivalized household disposable income. Equivalized means we take account of differences in household sizes. We don't think two people can live as cheaply as one, as the old adage goes, but we don't think two people need as much money as two single people living alone. I think the number comes out to about 1.4.
So we adjust for household size and take off the direct taxes and contributions that people pay. That brings it to disposable income. Then the poverty threshold we use is a relative threshold; it is half of the median of this equivalized household income.
The OAS plus GIS would bring you to about 90% of the poverty thresholds we have for Canada on this basis that we apply to all of the 30 OECD countries. So if you didn't have any CPP or private pension on top of that, then you would be below the poverty line.
In terms of poverty gaps—the distance that people are away from the poverty line—I think most people have incomes in Canada that take them quite a bit above. You are correct in your feeling that in some countries people are either a smidgen above or a smidgen below the poverty threshold because of the level of the safety net retirement incomes.