To the question: The low-income rate has been rising among the immigrant population as a whole, but one immigrant group saw its low-income rate fall over the past quarter century. Which group is it?
A. Immigrant children, or B. Immigrant seniors
The correct answer is B: The low-income rate among immigrant seniors was cut in half between 1980 and 2005, from 34% to 17%, which is only marginally higher than the rate among Canadian-born seniors, whose low-income rate was 13%.
In contrast, 27% of immigrant children lived in low-income families in 2005, up from 16% in 1980. This increase occurred while the rate among Canadian-born children was falling.
The low-income rate among immigrant seniors fell because they lived in families with higher market income (mostly income from employment), and because government social transfers reduced low-income rates among seniors as a whole. But in the case of immigrant seniors, the effect of rising market income was larger.
Chart - Low-income rates among immigrant children and seniors

Source: Census of Canada, 20% sample microdata files, 1981 to 2006.
Low-income rates are based on the total family income of seniors. If, for example, immigrant seniors were more likely to live in multi-generational families with more younger earners in 2005 than in 1980, this would be reflected in the rising market income available to them.
Table - Low-income rates among immigrant children and seniors
Source: Immigrant low-income rates: The role of market income and government transfers - HTML | PDF