Quality Assurance(QA): Quality assurance is a systematic monitoring and evaluation of the various aspects of a project, service, or facility to ensure that standards of quality are being met.Quality assurance(QA) reffers to the systematic activities implemented in a qualitysystem so that quality requirements for a product or service will be fulfilled. It is the systematic measurement, comparison with a standard, monitoring of process and an associated feedback loop that confers erroe prevention. This can be contrasted with quality control, which is focused on process outputs.
Quality control (QC): Quality control is a procedure or set of procedures intended to ensure that a manufactured product or performed service adheres to a defined set of quality criteria or meets the requirements of the client or customer. QC is similar to, but not identical with, quality assurance (QA). QA is defined as a procedure or set of procedures intended to ensure that a product or service under development (before work is complete, as opposed to afterwards) meets specified requirements. QA is sometimes expressed together with QC as a single expression, quality assurance and control (QA/QC).