With the extremely broad definitions of causation and duty we have seen adopted by the courts, and the destruction of such defenses as privity, assumption of risk, and product misuse, defendants have frequently looked to compliance with independent standards as a final safeguard against liability.
In a system in which liability was founded strictly on causation, without regard to the defendant’s intent, care, or negligence, such a defense would not be successful. Our system, however, is at least theoretically based on fault. In this system, compliance with independent standards set by the government or a trade organization, or simply by common use in the industry, would seem to imply non-negligence per se, particularly since negligence is usually defined in terms of "reasonable" behavior. Surely meeting government standards, or doing what everyone else in the market is doing, would seem to be "reasonable". If accepted, the defense would add considerable certainty to efforts to predict liability, especially in cases such as Koski and Eli Lilly, in which the injury was either not foreseeable or not preventable at the time of manufacture, because the manufacturer could meet definite standards and know that his product would be presumed non-defective by the courts.
Courts have long been reluctant to find defendants non-negligent on this basis, however, apparently on the theory that to do so would inhibit further safety developments by producers knowing that they were protected from liability so long as they adhered to standard methods.  Thus it is not a defense that a manufacturer complied either with statutory or regulatory requirements.  The Michigan products liability law of 1978  does allow such evidence to be taken into consideration by the jury in determining negligence, but compliance with independent standards is not a defense. 
The result is that proper design standards and standards of due care are determined by juries with no particular expertise in design or manufacture. These juries develop their standards on an ad-hoc basis influenced by the particular facts of each case and the emotional impact of the plaintiff’s injuries. Further, no matter how many lawsuits the defendant wins, he is never off the liability hook, since the next jury may decide that the design approved by other juries, a government regulatory agency, and the industry, is defective. Previous jury decisions exonerating the product and defendant are, of course, not admissible as evidence in the trial.
Naturally, when a jury can overrule a clean bill of health a product has received not only from the industry, but from government regulators, the insurer attempting to provide liability coverage for the manufacturer of the product can’t predict his liability exposure. Since this threat of liability always hangs over the product, the seller or insurer again resorts to adding an "uncertainty tax" to the premium.