It's a wonder that no one has done this yet (at least I haven't seen it), but half-an-hour on a spreadsheet this morning produced a most interesting, and surprising finding. First, some background.

Ontario is about to have a referendum on changing the way we elect governments from "first past the post" (i.e. the person who gets the most votes wins a riding) to MMP (whereby a portion of the legislature is appointed by the party based on party voting). This will allow, presumably, a party that gets 25% of the votes to have a larger representation in the legislature.

A couple of arguments swirl around the debate for MMP, both pro and con. One, is that a party that gets 44% of the popular vote will find it tougher to get a majority government. Second is that we will have less majority's, more fractious parliaments. Third is it will allow smaller parties to get representatives in the legislature. And my numbers say - all myths.

What I have done is take the last three elections, and extrapolate the numbers to the new system. So, the Liberals got 70% of the 103 seats in the last election, they get 70% of the 90 elected seats under MMP. Further, they got 46% of the popular vote, which I gave to them in the form of 46% of the 39 seats given for party vote under MMP. Here's my results;

The 203 election was a Liberal majority. The seats break down this way:

Liberals 72 (70%) - 46.4% of the popular vote
PC 24 (23%) - 34.6% of the popular vote
NDP 7 (7%) - 14.7%

Under MMP we would have a Liberal majority, with breakdown as follows

Lib: Elected seats 63; List members 18; Total seats 81 (62%)
PC: 21; 13; 34 (27%)
NDP 6; 6; 12 (9%)

1999 gave us a PC majority with PC's getting 57% of the seats, Liberals 29% of the seats and NDP 13. Under MMP

PC: 52; 18; 70 (54%)
Lib: 26; 16; 42 (32%)
NDP: 8; 5 ; 13 (10%)

And in 1995, Mike Harris' first majority. A quick summary, but under MMP

PC: 74
Lib: 33
NDP: 20

In each case, the governments popular vote was in the 45% range, in each case the results would not have changed, although the size of the majority's do. And in each case, no other party garnered the required 3% of the popular vote to get a "party list" seat.

A couple of provisos of note here. In some cases, I am measuring apples and oranges. As MMP has a separate voting mechanism for party list members, extrapolating pure percentage of popular vote isn't necessarily going to be accurate. The green party, for example, got 2.8% of the vote last election, but if given a separate choice, may very well have got quite a bit more. However, I am assuming that most people will vote for the same member and party. Also, three elections is a small sample. Done properly, such an analysis would go back 30 or 40 years, and examining the times when MMP would have changed results might even be more informative (the David Peterson Bob Rae years would be interesting to do, and how it would have affected minority legislatures would also be interesting). Finally, if you do some quick math, you will note that my numbers don't always add up. In each case the seats alloted is less that the 129 that would actually be given under MMP. This is a trick of percentages, and does not affect the end result.

I will make no comment on the data at this point, but am interested in others comments. I will make my opinion of MMP known later, but don't want to confuse this information with any argument I might make pro/con MMP. I did this for my own information, curious whether the arguments mentioned above hold water when tested against whatever data we have. They don't, so use that as you see fit.

Update: Never Mind:

As Eric points out in the comments, I seem to have gotten the formula for MMP wrong (although I'm still not 100% sure). My conclusions, in each case, are incorrect and invalid.