Last spring, the General Motors (GM) ignition switch fiasco garnered a lot of media attention with many people suggesting the National Highway Traffic Safety Administration (NHTSA) failed to act on consumer complaints and accident data related to airbag non-deployment in the 2005-2006 Cobalt and the 2003-2005 Ion. The NHTSA defended itself by arguing that several other vehicle models were receiving more complaints than the Cobalt and Ion, so there was not enough evidence to support a recall. However, a new study has shown the NHTSA's argument to be supported by an unscientific analysis of the data that doesn't support its claim.
The NHTSA first learned of the potential defect in the Cobalt's front airbags in 2005 after it was reported in a fatal accident that the airbag did not deploy. But it wasn't until nine years after the initial complaint that the NHTSA ordered a recall. When asked why it didn't act sooner, the agency has consistently placed the blame at the feet of GM, saying that the automaker didn't provide the agency with enough information to detect a trend. This claim was largely based on two analyses of crash-injury complaint rates in 2007 and 2010. The NHTSA's analysis of those complaint rates found the Cobalt and Ion had fewer complaints of non-deploying airbags than ten other non-GM vehicles.
David Freidman, the NHTSA's Acting Administrator, said in written testimony to the House Committee on Energy and Commerce that the agency's analysis provided no reason for GM vehicles to be on its radar. He even testified that vehicles manufactured by other automakers had significantly higher complaint rates, although the NHTSA never presented the data it was analyzing to Congress.
Study Shows NHTSA's Analysis To Be Unscientific
A statistical research firm, Quality Control Systems Corp., recently did its own analysis on the NHTSA data to see if it would come to the same conclusion. QCS filed a Freedom of Information Act request to obtain the data and run an analysis using classical statistical tests to determine if the differences in complaint rates that the NHTSA cited were statistically significant.
QCS found that there was no statistical significance in the complaint rates between the Cobalt, Ion and their peer vehicles. In fact, because the sample size of consumer complaints was relatively small, QCS went a step further and combined the Cobalt and Ion complaints and analyzed them against complaints about other vehicles. This analysis actually found that the complaint rates on GM cars were 54% higher than for the other vehicles.
Randy Whitfield, a principle of QCS, concluded that the "NHTSA was impressed by evidence no statistician would think was good, and the one piece of evidence that could have opened the eyes of a statistician was ignored. It's the style of analysis NHTSA has been using for years and years. If they see something that lets them off the hook, where they don't have to do hard work and they're not going to have to fight with a manufacturer, if you can give them the least scrap of evidence, they jump on it."
Numbers Don't Tell The Whole Story
It's not just the NHTSA's reliance on unscientific data analysis that's troubling, but a pattern of overlooking or ignoring clear trends that should've tipped the agency off to the problem with the GM airbags. After the recalls that took place last spring, a staff report from the Energy and Commerce Committee unveiled the NHTSA undertook he analysis only after the Early Warning Division had confirmed 43 accidents that resulted in 27 injuries and 4 deaths linked to airbags that did not deploy. The agency should have also noticed that GM warranty claim for Cobalt air bags was significantly higher than for other vehicles and that the manufacturer had already issued three technical service bulletins for its airbag system.
Even in the absence of properly analyzed scientific data, the NHTSA should have noticed a potential problem with the GM air bags based off the growing number of accidents and deaths, the high rate of warranty claims, and the GM technical service bulletins. Yet it still didn't open a full investigation into the matter. This suggests more than just a simple oversight or error in the analysis of the consumer complaint data; it suggests the NHTSA has a systemic problem in recognizing trends that show defective automobile parts.
Since the first recall of GM cars last spring, the manufacturer has initiated recalls on over 10 million other vehicles worldwide.