Nationally, IR is the most favourable pollster for the Conservatives. On average, they poll more than 3-points higher than anyone else. They are the least favourable pollster for the NDP, polling them more than 2 points lower than the other pollsters. They're middle-of-the-road for the Liberals and Greens.
In Quebec, they are the most favourable pollster for the Conservatives, but still only giving them about 1.5 points more than everyone else.
For fun, here is the last Ipsos-Reid national poll, adjusting for the discrepancy:
Conservatives - 35.7%
Liberals - 28.4%
New Democrats - 16.5%
Greens - 10.7%
And Quebec:
Bloc Quebecois - 33.6%
Liberals - 28.6%
Conservatives - 18.5%
New Democrats - 9.4%
Greens - 8.8%
The chart below tracks how each pollster tends to lean when calculating support levels for the various parties, as compared to the average polling results from other pollsters each month. This does not necessarily equate to a deliberate bias, but instead is more reflective of the polling methods used.
The following chart shows each pollster's average variation from other polling firms. The numbers are the amount of percentage points a particular pollster favours or disfavours that particular party compared to other pollsters over a similar period of time.
