Burton Malkiel is one of the greatest investment thinkers of all time. Regardless of whether you agree completely with his landmark bestseller A Random Walk Down Wall Street, he provides a compelling case for a low-cost, low-turnover investment strategy as the road to wealth for most people. He had an interesting editorial in Monday's Wall Street Journal where he discussed the possibility of irrational complacency about the current status of the economy.

After going through a series of possible concerns for stock market investors (instability in the Middle East, the trade deficit, income inequality, etc.), he writes that "As a believer in efficient markets, I hesitate to conclude that our markets are being irrationally complacent. I believe that markets are high and risk spreads compressed because of massive increases in world liquidity...So what should investors do as the Dow rises to new highs? Should they "sell in May and go away," as one stock-market bromide suggests? As a student of markets for over 50 years, I am convinced that attempting to time the market is a fool's game. But new highs in the market should induce investors to review their asset allocations. If the rising stock market has pushed your allocation of equities well above the level consistent with your risk tolerances, it makes sense to consider rebalancing..."

He also cautions that investors are unlikely to make money in the long-run betting against the strength of the U.S. economy. His investing strategy has remained essentially unchanged since his book was originally published in 1973, and it's a strategy that has outperformed the vast, vast majority of market pundits with a lot less work.

I'm inclined to agree with his advice for investors -- Don't jump in and out based on the market's movement. Rebalance annually and relax. And read Malkiel's book.