Big fan of any data aggregation projects like this, especially with such a relatable theme.

However it feel like the conclusion might be jumping the gun a bit. Instead of "Think there is collusion" -> finding the data top support the claim, maybe run the numbers first and see what they say? I think coming up with a strong position (Canadian stores are colluding) before looking at the data makes it enticing to find numbers that back up the claim, whether or not they are taken out of context.