Bargain shoppers are adept at finding high quality at low cost, and investors like Vanguard founder Jack Bogle have argued that strategy reaps rewards for fund investing, too.

That philosophy now has statistical backing: Recent research from Morningstar indicates lower expense ratios often result in better performance.

Expense ratios are the most effective predictor of investment performance, according to “Predictive Power of Fees: Why Mutual Fund Fees Are So Important,” a whitepaper from Russel Kinnel, Morningstar’s director of manager research,

Morningstar divided funds within each of its categories into quintiles based on their expense ratios, then compared the quintiles' performance over a five-year period ending in December 2015. A quintile's "success ratio" measures the percentage of funds that outperformed their category group using total returns while factoring in the number of funds that were merged away or liquidated over the time period. Only funds that both survived and outperformed counted towards their quintile's success ratio

U.S. equity fund quintile with the lowest expenses registered a 62 percent success ratio over five years, more than triple that of  funds in the highest expense quintile, which had a 20 percent success ratio.

In the taxable bond category, funds with expense ratios in the lowest quintile outperformed the highest-expense quintile by 3.5 times, a 59 percent success ratio for the cheapest funds verses 16 percent for the priciest quintile.

Even among international equity funds, expenses mattered more to performance than volatility and management, though the differences were narrower, Morningstar said. The lowest-cost quintile of international equity funds reported a 51 percent success rate, nearly 2.5 times the 21 percent success rate of the most expensive quintile.

Across every asset category, including international equities and sector equities, the funds with the lowest expense ratios recorded the best performance over three, four and five-year time periods, and when comparing any two quintiles within a category, the lower-expense funds outperformed the more expensive ones without exception.

Funds with lower expense ratios tend to have longer lifespans, according to Morningstar.