[Editor's Note: This article is part of GreenBiz.com's coverage of the 2009 Business for Social Responsibility conference. To read all our coverage, visit GreenBiz.com/BSR2009.]

Increasingly, voluntary sustainability reporting is becoming a mainstream practice. Yet with the global economy still roiling, trust in business remains low and the question of mandatory reporting is being raised with greater persistence.

The question and issues surrounding it -- what to report, how much, to whom, who finds them important and who reads them -- were the focus of a panel discussion at the 2009 Business for Social Responsibility conference in San Francisco.

"We are still in a situation in which trust in business is still really low," said Doug Bannerman, BSR's senior manager for advisory services and moderator of the panel "From Voluntary to Legal Disclosure: Should Sustainability Reporting Be Required?"

"In the course of the last 10 or 12 years, reporting has become mainstream, yet we keep coming back to these issues of trust," Bannerman said, noting that news reports of the failure of more than 100 U.S. bank so far this year is not likely to help foster a resurgence of trust in business.

There are, he said, "constituencies who say maybe voluntary (reporting) isn't enough, maybe reporting should be mandatory."

Bannerman's intro launched a lively and often humorous hour-long dialogue with Gary Niekirk, director of global citizenship at Intel, and Jerome Tagger, chief operating officer at Principles for Responsible Investment.

Intel's compiled its first report on environmental, health and safety issues in 1994, said Niekirk. For the past decade, the company has followed Global Reporting Initiative guidelines in drawing up its Corporate Social Responsibility reports -- the most recent of which followed G3, the latest version of the reporting framework.

Nevertheless, Niekirk said, he would not recommend making a case for mandatory reporting based on return on investment, given studies on whether a correlation exists between environmental, social and corporate governance reporting and ROI. About half have found a positive correlation, 35 percent were neutral and about 15 percent didn't support the hypothesis.

Niekirk likened the situation to a doctor telling a patient to take vitamins based on findings from 20 studies, 10 of which found a correlation between taking vitamins and good health, seven of which were neutral and three were negative. "And then, what if you were told the vitamins would cost you 50 bucks month ... " he said.

Drawing a parallel to the issue of reporting, Niekirk said, "maybe citing ROI is the wrong focus, maybe the issue is accountability."

PRI, Tagger said, does not take a position on mandatory reporting. The organization's six principles are a framework for responsible investment practices but they're not a compliance framework, he emphasized. However, many of the firms that are signatories to the principles, do take a position on the issue, he added.

"Disclosure is a big word and a scary word, and because disclosure means reporting it means work," Tagger said as the discussion moved to the question of costs, including investments in time for compiling the reports, potential expenses for putting together more comprehensive reports if they become mandatory, and, possibly, fees for third-party auditing.

Tagger suggested that before delving into costs, more basic matters need to be sorted out.

"I think the primary point is -- even before we get to the question of mandatory or not -- is what do we report, to whom and why," Tagger said.