Software Inspection
Software inspection is a well-known method of cost-effectively verifying documents, 
  first described by Michael Fagan in 1976. The benefits of inspection are generally 
  accepted, with success stories regularly published. In addition to Fagan's papers 
  describing his experiences, there are many other favorable reports. For example, 
  Doolan reports a 30 times return on investment for every hour devoted to inspection. 
  Russell reports a similar return of 33 hours of maintenance saved for every 
  hour of inspection invested. These benefits are derived from applying inspection 
  early in the lifecycle. By inspecting products as early as possible, major defects 
  will be caught sooner and will not be propagated through to the final product, 
  where the cost of removal is far greater.
Much of the current (and future) work (in software inspections) focuses on 
  supporting the inspector to handle the ever increasing complexity of software systems