Lever points (also named 'Leverage Points') in a complex adaptive system are according to John H. Holland points at which a small effort can produce a desired, directed effect. They are places within a complex adaptive system where a little change makes a big difference and a small shift a big change. At these critical transition points the behavior of a complex system changes fundamentally. They are similar to Gell-Mann's frozen accidents. Lever points identify places to intervene in a system.
John H. Holland writes about them (see here)
- "Almost every complex adaptive system that we know of has lever points. These are great things if you can find them. A lever point allows you to make big, directed changes for a relatively small effort. A vaccine is a good example of a lever point. An immune system is terribly complex. But we do know that for some diseases, we can make a small injection and train the immune system to resist a disease for the rest of its existence — much longer than the life span of any blood cell in your body."
see also butterfly effect, path dependence, frozen accident
If there are only a few lever points, where a small effort can produce a large effect, then the majority of points and events are ordinary points, where a small effort has only a small or even vanishing effect. These are points where a little change makes only a little difference.
- The Scientist article from John H. Holland Biology's Gift to a Complex World
- Paper from Donella Meadows about Leverage Points