The idea of the exchange based funds is that they dynamically adjust the holding of each issue on a particular exchange or group of exchanges based on the value market capitalization of each issue. That way, the coverage of low capitalization issues is limited because they don't compare to the bigger issues.Index funds and a lot of ETFs have "managers" who follow a "formula". These are not considered "managed". The industry term is passive managed. The active managed funds have managers (and researchers) who are supposed make trades that out perform the market. That doesn't happen too often
The idea is that you are exposed to a reflection of the total economy. If you have both NASDAQ and NYSE funds, you are going to have a reasonably efficient investment strategy without the added cost of managed funds. But you are, of course, entirely basing investments on equity positions unless you balance with various types of federal, state and private bonds.
