Misunderstanding Requirements often leads to Product Development Errors

Unclear requirements language — whether expressed as requirements or user stories — may result in building the wrong product, or wasting time and money building to a misunderstood specification, or even safety issues. A number of studies found approximately 400 of every 1000 defects in safety critical systems are inserted during the Requirement development stage.1,2   The defect ratio is lower, but still very high in non-safety critical systems development projects.

Requirements engineering stretches the capabilities of our language to be precise compounded by product development teams made up of experts with training in different fields. For examples, business and technical professionals will not understand each other’s terminology. Even worse, each discipline can have a different meaning for the same words.  See graphic below for a typical communication issue.

C9 Course Overview graphic


  1. Jones, C , 2011. The Economics of Software Quality.
  2. Robyn Lutz’s 1992,  Analyzing Software Requirements Errors in Safety-Critical, Embedded Systems (1993)