• It is one of the type of non-functional testing.
• It refers to the validation of documents and specifications on which test cases would be designed. The requirement specification validation is baseline testing.
• Generally a baseline is defined as a line that forms the base for any construction or for measurement, comparisons or calculations.
• Baseline testing also helps a great deal in solving most of the problems that are discovered. A majority of the issues are solved through baseline testing.

Other popular articles:

• What is Validation in software testing? or What is software validation?
• What is test coverage in software testing? It’s advantages and disadvantages
• What is a proof-of-concept or piloting phase for tool evaluation in software testing?
• How to pass ISTQB Foundation exam certification in your first attempt
• What is Non-functional testing (Testing of software product characteristics)?