This is my experience. The last company I worked for that did layoffs while I was there was an example. None of the middle managers had any input in the firing decisions at all. They were just given a list of names by upper management. They were very upset about it, because they couldn't lay off people that were underperforming and were forced to lay off people who were critical or performed very well. Many of them said that it didn't appear that the decision-makers even looked at performance reviews, either. It appeared random.