Although stocks started 2016 by tumbling, the market didn’t seem quite so scary by the time the first quarter ended last week: Both the S&P 500 and the Dow Jones Industrial Average eked out small gains for the three months through March. And history suggests investors should be optimistic about positive returns for the full year, San Diego-based adviser Kevin Clewley tells WSJ.com’s Wealth Adviser. Going back to 1980, the S&P 500 (with dividends reinvested) posted positive returns in 30 of those 36 years, or 83% of the time, Mr. Clewley notes. That track record occurred despite temporary pullbacks of 5% to 20% during almost every one of those positive years. When all is said and done, 2016 might not see a return as rich as the 13.5% of 2014, but it could well be greater than the 1% return last year, he adds. And telling clients about the record of recent decades might give them the confidence to ride out corrections and remain invested.