Quality asssurance (QA) applies the big picture of quality to give the confidence that deliverables are being designed and developed according to the requirements and the appropriate standards. There is often confusion between quality assurance and quality control (QC). QC is the ongoing control and measurement of quality, whereas QA is the check that everything is going to plan. The easiest way to check for quality is through inspection. Inspection can be used for physical components and deliverables as well as business procedures. Sampling is often used as a gauge of quality. Sampling can take various forms and will depend on the type of project being undertaken. The prime opportunity for conducting quality assurance in a project is through a series of scheduled QA reviews. The Quality Plan refers to the measurement criteria and test criteria for deliverables, plus the quality objectives and acceptance criteria, all of which are necessary information for a QA review.