Product life cycles (as measured from R&D to product end of life). Presumably, companies sell products only as long as it makes economic sense to do so. The knowledge assets required to produce a product have value as long as the product can be profitably sold. Since product life cycles tend to be long for chemicals and pharmaceuticals and short for computers, we would expect the knowledge assets in the chemical or pharmaceutical industry to depreciate more slowly
than in the computer industry. Pharmaceutical companies have long product life cycles, due to the difficulty of the drug discovery process itself, and the long clinical testing and regulatory approval cycles. Computer industry product life cycles are currently tied to the development of the next generation of microprocessors, and computer system design knowledge
is quickly made obsolete.