Frank Neuhauser, a professor at the University of California at Berkley, echoed Mr. Boden's sentiments, adding that an accurate depiction of how often workers are getting injured can help an employer determine how much they need to worry about their employees' safety.

“There really is a lot of concern about underreporting injuries, because it means less investment in safety,” he said.

Measuring unreported injuries is “difficult,” Mr. Boden acknowledged. Few studies have been conducted on the issue, and those that have been were generally limited in scope to one jurisdiction or type of injury.

Mr. Boden conducted his own study over six states and found that–depending on the assumptions used in analyzing the data–it is possible that as many as 55 percent of workplace injuries could go unreported in some states. Using more conservative assumptions, he noted, the average of the six states was roughly 22 percent.

There are several reasons why injuries go unreported, Mr. Boden noted, and among the most important is the view that employees take of workers' compensation.

“People look at it like they used to look at welfare–that it's something you shouldn't do; it makes you a bad worker,” he said.

Decreased benefits also provide less incentive to seek workers' comp, he noted, and lower-income workers may also fear losing their job–or, in the case of illegal immigrants, being deported if they file a claim.

Another key factor Mr. Boden noted was what he called “workers' comp hassle,” or the difficulties of filing a claim, keeping track of paperwork, and if necessary, challenging a denial.

Mr. Neuhauser's study found that a significant number of injuries–as much as 20 percent–are being filed as claims for social disability programs, such as Social Security or a similar state fund that is financed by taxes on employees, rather than with a workers' comp insurer.

This overlap, he argued, could be resolved by establishing one program that would cover both workplace injuries and those covered by social insurance programs, and the cost wouldn't be as burdensome as would be expected.

According to Mr. Neuhauser, a combined insurance program would only increase employers' expenses by .13 percent of their payroll, yet it would resolve many of the issues that confuse the current system by allowing for costs to be more accurately determined, and would reduce litigation over disputed claims.

Increasingly, workers also have to overcome the obstacle of resolving their workers' comp claims alongside the Medicare system, according to Edward Welch, director of the Workers' Compensation Center at Michigan State University.

Congress during the 1980s passed a law that established Medicare as the secondary payer when an eligible worker suffers a compensable injury. In cases where Medicare paid for treatment that was eventually ruled an obligation for a workers' comp insurer, the carrier is required by law to reimburse the program, and enforcement of that provision has been strict since 2001.

“There's no question today, you reimburse Medicare,” Mr. Welch said.

The problem, he noted, is that the Centers for Medicare and Medicaid Services has established a number of requirements that make the claims process, or the settlement process, more difficult and time consuming.

CMS requires that settlements are pre-approved by the agency. This can cause significant delays–he noted there are currently 900 cases “on hold” in Michigan awaiting CMS approval of a settlement agreement.

Mr. Welch said there does not appear to be any legal right for CMS to require the pre-approval. In fact, he noted, a similar provision for Medicaid recipients was struck down by the courts. But he also acknowledged that few, if any, claims managers would be willing to fight the legal battle to extend that ruling to Medicare.