Many of us get confused as to what is quality assurance and what is quality control on a software project. Let us discuss the differences in this post.
Quality control has 2 aspects. First it refers to measuring attributes of a product and comparing these measured values with the expected values for these attributes. If the measured values differ from expected values then quality of the product is considered bad and it means the product is defective. on the other hand, if these values are close to each other then quality of the product can be considered good. After a product is identified to be defective then it is either reworked to make it defect free or it is rejected. So quality control takes no cognizance of the processes involved in making the product and it only focuses on the product attributes.
Quality assurance on the other hand does not look at product attributes measurements or making a defective product defect free. It focuses on the processes involved in making the product and refines these processes to make sure that the product made has good qualities. Off course, the product attributes will be measured in this case as well to know if the product has good quality or not but the focus is not on fixing those defects. Rather it is improving the process to make sure that the product defects which occurred in previous process model will not occur after the process model is refined.