Background check involves everything. Past history, travels to various countries et al. So if any thing, currently being in land adds two countries to be evaluated against your profile (that of citizenship AND Canada) as opposed to some one who never left their home country. This multiplies if a person has lived in several of those. Hence its hard to generalize.
Update: It also includes security checks - which involves comparing your name against a global data base of known criminals. So often, having a common name results into longer background checks as opposed to having a unique name.
