Ranking seven persons or seven anything in order is known in psychology as a human limitation. I think Raymond Côté will speak more about that in a few minutes. It's just a limitation of the human brain.
I saw this in the French election, an experimental election they did. They asked people to use other voting systems, and in one of those you ranked your candidates. People were pretty reasonable for the first seven, but then the system crashed and it became random. At that point, it was more than what the human brain can do. It was just too hard.
I have a post-doctoral person in my university who is living in India, and they have sometimes tens of candidates on the voting tickets. They are that large, and it's just impossible to do. Some people say we could just have a cut-off and order the first five. Depending on the voting system, some might allow that and some might not.
As for the voting systems using some kind of ranking, there are about 20 of those. There is one, STV, which is used in Ireland, but I don't have much expertise on that. One that is very good is the Borda count, in which you give points depending on the order. I think it's done the way journalists might find the best hockey team. It's five points for the first one, four points for the second. It's very simple arithmetic. You find the best candidate defined as the most central one, the guy or woman who is most average. It's very nice if you want to elect a president or you want someone who represents the population.
There is a philosophy here. Do you want that for an MP, a member of Parliament who represents a riding? Do you want the best average guy, or do you want a Parliament that is very diverse? If you go for that, you willl end up with the most central parties. In Canada, in most cases, it would be the Liberal Party or the Conservative Party. In some regions the NDP might be considered more central. You end up with a concentration.
I did a simulation in Quebec. I've never done it in Canada. In Quebec I ended up with Liberal, PQ, and three or four members of the ADQ. It usually wipes out those who are somewhat less central and it converges towards two parties. That's what we are supposed to fight against now.
I would use this in one case, though: the case of partial elections. At that point, you might want to reset the system to get a replacement guy. We're replacing the actual MP. We'll use one of those sophisticated methods to find the best average guy for the rest of the term. It might give a chance to another party that otherwise would not be detected by the system.