About this Ontario poll from Mainstreet Research
This Ontario poll was fielded by Mainstreet Research in May 2019, with a middle field date of May 22, 2019. The poll collected data from a total sample of n=996 Ontario respondents via IVR technology (automated calls).
The margin of error for an online sample is not applicable.
For comparison purposes, a random sample of this size would yield a margin of error [moe] of ±3.1%, 19 times out of 20 (for entire sample only) around the 50%-mark.
The regional breakdown of this poll was not made publicly available.
If we compare these national numbers with the previous poll from Mainstreet Research (March 2019), the Ontario Liberal Party climbs 13 points from 26% to 39%, the Ontario NDP loses two points from 26% to 24% (variation smaller than moe), and the Ontario PC Party loses 12 points from 34% to 22%.
You can read more information on this poll here.