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Software Product Liability

August 1993 Technical Report
Jody Armour (School of Law, University of Pittsburgh), Watts S. Humphrey

This 1993 Software Engineering Institute (SEI) report explores the effects of software defects.


Software Engineering Institute

CMU/SEI Report Number



Software defects are rarely lethal and the number of injuries and deaths is now very small. Software, however, is now the principle controlling element in many industrial and consumer products. It is so pervasive that it is found in just about every product that is labeled electronic. Most companies are in the software business whether they know it or not. The question is whether their products could potentially cause damage and what their exposures would be if they did. 

While most executives are now concerned about product liability, software introduces a new dimension. Software, particularly poor quality software, can cause products to do strange and even terrifying things. Software bugs are erroneous instructions and, when computers encounter them, they do precisely what the defects instruct. An error could cause a 0 to be read as a 1, an up control to be shut down, or, as with the radiation machine, a shield to be removed instead of inserted. A software error could mean life or death.