Remember Murphy’s Law: What can go wrong will go wrong. And don’t forget O’Toole’s commentary: Murphy was an optimist. Bad things do happen to good p… - Burton Malkiel

Investors should certainly be aware of new methods of portfolio construction. And high net worth investors might consider adding a multifactor smart beta offering or a risk-parity portfolio to the overall mix of their investments. Factor investing can potentially increase returns at the cost of assuming a somewhat different set of risk exposures than those of a standard broad-based index fund. And investors who are able to accept the added risks inherent in leverage might profitably add a risk-parity portfolio to their set of investments. Such offerings should only be considered, however, if they are low cost and if their potentially adverse tax effects can be offset in other parts of the overall portfolio. And I continue to believe that a broad-based total stock market index fund should be the core of everyone’s portfolio. Certainly, for investors who are starting to build an equity portfolio in planning for retirement, standard capitalization-weighted index funds are the appropriate first investments they should make.

Why are memories so short? Why do such speculative crazes seem so isolated from the lessons of history? I have no apt answer, but I am convinced that Bernard Baruch was correct in suggesting that a study of these events can help equip investors for survival. The consistent losers in the market, from my personal experience, are those who are unable to resist being swept up in some kind of tulip-bulb craze. It is not hard to make money in the market. What is hard to avoid is the alluring temptation to throw your money away on short, get-rich-quick speculative binges. It is an obvious lesson, but one frequently ignored.

Before we can determine a rational basis for making asset-allocation decisions, certain principles must be kept firmly in mind. We’ve covered some of them implicitly in earlier chapters, but treating them explicitly here should prove very helpful. The key principles are: 1. History shows that risk and return are related.
2. The risk of investing in common stocks and bonds depends on the length of time the investments are held. The longer an investor’s holding period, the lower the likely variation in the asset’s return.
3. Dollar-cost averaging can be a useful, though controversial, technique to reduce the risk of stock and bond investment.
4. Rebalancing can reduce risk and, in some circumstances, increase investment returns.
5. You must distinguish between your attitude toward and your capacity for risk. The risks you can afford to take depend on your total financial situation, including the types and sources of your income exclusive of investment income.