"Review" is one of the key words when talking about the software testing. The reviews should not be necessarily carried out by the testers, but by the people to whom the project manager will assign this task (especially by the quality assurance department, if this exists within the company) .
We can review a lot of aspects during the software development life cycle: development and design documentation, test plans, test cases, test results, defects, tests and development metrics, etc.
Even if we are doing informal, walkthrough, technical or inspections reviews (I'll try to detail each of these types in the next posts) it is important to distinguish between the factors which make a review to be successfull or not.
We need to make sure the right people are involved for the review objectives, the review's objective is clear for all participants, each issue found is expressed objectively without affecting the author (it has to be a constructive action and not a "witch hunt"), we use checklists in order to be more effective in identifying the issues, adequate time for reviews are allocated in the project shedules, etc.
In case that the responsibilities are not taken seriously or understood, the allocated resources are insufficient or the processes to support reviews are insufficient (or don't exist) then we can talk about unsuccessfull reviews.
Only by reviews we can make sure that the system specifications/requirements are correct and important faults are found before coding has started.