I Wonder how the drops work. I have multiple players with a drop rate around 10%. Some of them have a good Pass Catching attribute. So i've checked my league. The players that have the most drops have a very good PC.
Does the QB affect the drops by the way he throws ? My QB is a first year starter, so that could be an explanation. Or it's total random, and it's just bad luck. But I find strange to have a lot of drops by 80+ PC players.

Without doing a lot of research into my past games, and perhaps I just notice it more than it happens, but I seem to see the 'pass was behind the receiver' line when I have drops. Not all the time though.

A drop means the ball was close enough for the receiver to touch it (the old adage if you can touch the ball you should be able to catch it). Besides the catching attribute, other factors include the position of the ball (the accuracy of the QB), the WR's fatigue, and an incoming defender (punish receiver vs courage, even if the DB doesn't make contact with the WR if he has a high punish receiver and the WR has a low courage he'll brace himself and drop the ball)