Statistics of design error in the process industries

The paper addresses questions on how frequently incidents and accidents are caused by design errors and how significant design reviews are in removing design errors before a system is put into operation. It is based on a review of earlier studies mainly from the chemical and nuclear industries. The studies report that from about 20% to 50% of the studied incidents and accidents have at least one root cause attributed to erroneous design. The number of design errors actually occurring during the design process is much higher, but 80–95% of them are removed by thorough design reviews. To improve the design process further, it is necessary to analyse the nature and causes of design errors through first hand knowledge about the design process.