Gerhard's management skill was the most obvious factor common to the failed projects, but it wasn't the cause. In this case, faulty reasoning damages a career and deprives the company of a skilled manager.
How can you spot this kind of error in the heat of debate? The fallacy of the false cause might be lurking if the argument states that:
Since A was present when B occurred, then A was the cause. Or Since A preceded B, A caused B.
To respond to arguments that use this fallacy, use examples in which A was present, but B wasn't. Your debate partner might not be convinced, but it's your best shot.
Educate your colleagues about the Fallacy of the False Cause. When we understand how much it can cost, and when we understand how to avoid it, we can save much pain and frustration. Perhaps Will Rogers said it best:
It's not what we don't know that hurts; it's what we know that ain't so.