This morning's Hill Times writes about how the two main parties are targetting the ridings won by less than 5% of the vote last time (i.e., MargPct < 5%). This criterion also appears as one of "Election Pundit Queries found on the Browse Elections page in this database, allowing you to see quickly which ridings those are for all past elections, called "Closest contests (MargPct <= 0.05)".

At least one writer tonight, however, is questioning whether a close margin should be the only criteria for targetting ridings likely to change hands again.

Naturally, it makes sense to consider the 2006 results as a relevant factor in allocating resources. But any party which relies unduly on 2006 alone as its baseline figures to miss a significant portion of both the risks and the opportunities facing it next time out. -- Accidental Deliberations

So, I decided to do an analysis that compared seats previously won by margins of < 5% against Ridings that changed hands party-wise in an election (another Election Pundit Query), to see how well a narrow margin predicted later riding turnovers. Here are the results:

Distribution of seats by Hold vs. Change and Previous Percent Margin of Victory, 1997-2006

	Under 5% Hold	Under 5% Chng	Over 5% Chng	All Under 5%	All Chg
2004 -> 2006	33	25	30	58	55
2000 -> 2004	11	28 (24)*	39	39	63
1997 -> 2000	21	15 (11)*	22	36	55 33

* reflects adjustments between the 2000 General Election results on the 1996 Redistribution boundaries and the 2000 Transposition results on the 2003 Redistribution boundaries.

The statisticians out there can run the chi-squares on this, but my Coles Notes version is that, in each of the three cases here, more seats changed hands where the previous margin of victory had been over 5% than did under it.

[UPDATE: Fixed transposition error in the table.]

Labels: Close Margins, Data Analysis, Seats that changed hands