The AP reports that since the 1990s, the height of concern over the issue, "carpal tunnel cases have plummeted, declining 21 percent in 2006 alone, according to the Bureau of Labor Statistics. Among workers in professional and business services, the number of carpal tunnel syndrome cases fell by half between 2005 and 2006." Researchers are concluding that while repetitive stress injury, to use another catch-phrase, is indeed a serious job hazard for some workers who engage in physically demanding tasks like meat-cutting, mattress-flipping, and so forth, it was greatly overdiagnosed or misdiagnosed as a malady afflicting computer keyboard users. (Ergonomic improvements such as wrist rests for mouse pads have undoubtedly helped, but are unlikely to explain the whole drop, especially since time devoted to keyboarding among the population seems to be rising steadily.) "A 2001 study by the Mayo Clinic found heavy computer users (up to seven hours a day) had the same rate of carpal tunnel as the general population. Harvard University headlined a 2005 press release 'Computer use deleted as carpal tunnel syndrome cause.'"
The AP account is worth reading in full, but it entirely omits one of the explanatory variables that might be salient. At one point, RSI-carpal tunnel-cumulative trauma was seen as one of the more promising product liability mass torts, with lawyers around the country filing thousands of claims; the favored targets were deep-pocket equipment makers such as IBM and Apple. The suits gathered steam and moved forward for several years but suffered a crushing setback when a federal appeals court in 1993 reversed an order consolidating many such cases (In re Repetitive Stress Injury Litigation, 11 F.3d 368 (2d Cir. 1993)). When pursued individually most of the cases fared poorly, and the prospect of a "bet your company" mass verdict was no longer there to serve as leverage to get defendants to the settlement table. The result was a rout for plaintiffs and an unusually thorough win for defendants: RSI-carpal tunnel litigation has subsided and is no longer seen as a threat to the financial health of computer makers, and most lawyers have given up on it.
But what if the Second Circuit had acted differently in 1993 and allowed the mass cases to move forward as a consolidation? What if rather than risk a "bet your company" trial, defendants had one by one begun signing up for a settlement fund to compensate sufferers? What if -- after the lawyers and experts took their billions -- billions were left over for persons who could produce a doctor's note attesting that after they used computers their joints ached in certain ways? Is there really any doubt that the number of newly reported cases would today be far higher, and perhaps would not have declined at all? Is there any doubt that a large body of opinion would now angrily reject the reassuring Mayo and Harvard findings, on the grounds that -- to quote a phrase heard in both the silicone-implant and autism-vaccine episodes -- "We are the evidence."
Some, of course, will draw from all this the conclusion that carpal tunnel is just as real and frequent an ailment as ever but is now being seriously underdiagnosed because workers are ever more discouraged from even so much as reporting it, knowing there will be no remedy. Others will conclude that our legally driven compensation system is quite good at calling forth subjective or hard-to-disprove claims of injury, and that we owe the Second Circuit thanks for a narrow escape, not only from a gigantic and spurious episode of mass tort litigation, but indeed from a whole spurious public health epidemic that would otherwise be raging on to the present.