QA is a set of activities for ensuring quality in the processes by which products are developed.
QC is a set of activities for ensuring quality in products. The activities focus on identifying defects in the actual products produced.
Focus on –
QA aims to prevent defects with a focus on the process used to make the product. It is a proactive quality process.
QC aims to identify (and correct) defects in the finished product. Quality control, therefore, is a reactive process.
The goal of QA is to improve development and test processes so that defects do not arise when the product is being developed.
The goal of QC is to identify defects after a product is developed and before it’s released.
Prevention of quality problems through planned and systematic activities including documentation.
The activities or techniques used to achieve and maintain the product quality, process and service.