Shareholder support for executive pay plans may be weakening, but do shareholder votes really matter in the final determination of executive pay? More than 40 percent of institutional investors don’t believe so.

According to a new study from the Stanford Graduate School of Business, more than four in 10 institutional investors believe that their say-on-pay vote ultimately has no influence on what executives are paid. Furthermore, only 38 percent of the 64 surveyed asset managers believe that corporate disclosure about executive compensation is clear and easy to understand.

“Shareholders want to know that the size, structure, and performance targets used in executive compensation contracts are appropriate,” says Stanford professor David F. Larcker. “Our research shows that, across the board, they are dissatisfied with the quality and clarity of the information they receive about compensation in the corporate proxy. Even the largest, most sophisticated investors are unhappy.”

Part of the unhappiness is due to the structure of corporate proxy statements. The survey indicates that 55 percent of investors believe that proxy statements are generally too long, and the investors only read 32 percent of the average statement. The investors say that the ideal length of a proxy statement is about 25 pages, although the current average statement length is 80 pages.

The numbers are perhaps surprising given the emphasis that many shareholders place on these votes. The same survey found that 80 percent of shareholders believe that proxy voting increases shareholder value.

However, there is hope that these statements can be fixed. “Investors are noticing the wide range in quality and clarity among various companies’ proxies. They want companies to communicate and explain, rather than simply disclose,” adds Ron Schneider, director of corporate governance services at RR Donnelley Financial Services Group, a partner with Stanford on the study. “This represents a significant opportunity for many companies to improve the clarity of their proxies.”