> Collusion is a deceitful agreement or secret cooperation between two or more parties to limit open competition by deceiving, misleading, or defrauding others

> Collusion is a deceitful agreement or secret cooperation between two or more parties to limit open competition by deceiving, misleading, or defrauding others of their legal right. [1] If you decide, on your own, to sell a product at a lower price than your competitors, you are doing exactly what capitalism expects from a free market. If you call the neighboring stores and say "hey, let's all sell apples for 2x our current price so consumers don't have a choice but to buy it for that price", then you are colluding. Your point does stand though. From the outside it's very hard to distinguish between collusion and not by mere correlation. Prices may converge for various legitimate reasons, and without insider knowledge, reliably identifying collusion is often impossible. The best-case scenario for the project might involve comprehensively modeling a single product category to demonstrate that only collusion could explain the pricing patterns. Success would then hinge on litigation uncovering direct evidence like incriminating communications. [1] https://en.m.wikipedia.org/wiki/Collusion https://en.m.wikipedia.org/wiki/Collusion