It is not just Economics that have Zombie Ideas.

I believe that the term Zombie Idea was coined by Paul Krugman. It refers to an idea that while discredited keeps coming back. In Economics it is things like Austerity, Trickle Down Economics, or the idea that Tax Cuts will increase Tax Revenue (Laffer Curve)

In Education probably the best known Zombie Idea is that of Learning Styles. Here is an blog post from OldAndrew that makes the point yet again that there are NO Learning Styles.