There's been some research done by academics who reckon that balancing a portfolio based on inflows and outflows from sales of shares can outperform the stock market.
http://www.ft.com/cms/s/0/cbcb5c58-405e-11e1-8fcd-00144feab49a.html
http://www.ft.com/cms/s/0/cbcb5c58-405e-11e1-8fcd-00144feab49a.html