Quality Assurance vs. Quality Control

Differentiate between

a.) Software Quality Assurance and Software Quality Control
b.) Severity and Priority
c.) Clear box testing and Ad-hoc Testing

a.) Software Quality Assurance and Software Quality Control
SQA verifies if the process that is followed to create a product is effective and does not contain process defects whereas SQC verifies the actual product itself.

b.) Severity and Priority
Severity is the level of impact, a bug will have on the application if undetected whereas priority is the order in which the bugs needs to be fixed. A severe defect will always have higher priority but the reverse may not always be true.

c.) Clear box testing and Ad-hoc Testing
Clear box testing is white box testing which is a structural testing technique. It requires understanding of the internal logic and flows of the program. Ad-hoc testing is black box testing which is functional testing technique. It is a type of exploratory testing done without following any documentation.

What is the difference between Quality Assurance and Quality Control?

Quality Control is work product oriented while Quality Assurance is work process oriented. This can be further explained as QC is ensuring that the final product works correct; whereas QA is ensuring that the processes and methods used while developing that product are correct. This tells us that QC is detective (ie it detects and fixes any bugs in the s/w) while QA is preventive (ie it prevents bugs from occurring in the first place)

One of the examples of QC is S/w testing while example of QA is Audit.

Often o/p of QC is used as i/p to QA to examine and revise the strategies and processes used.