Static Vs Dynamic Testing

Static Testing-

Static testing relies on the manual examination of work products (i.e., reviews) or tool-driven evaluation of the code or other work products (i.e., static analysis). Both types of static testing assess the code or other work product being tested without actually executing the code or work product being tested. It is basially testing of Software development architect without execution of these architect.

Static analysis can even be applied with tools that evaluate work products written in natural language such as requirements (e.g., checking for spelling, grammar, and readability).

Dynamic Testing-

Dynamic testing executes the software and validates the output with the expected outcome. Dynamic testing is performed at all levels of testing and it can be either black or white box testing.

Difference between Static and dynamic Testing-

• Static testing finds defects in work products directly rather than identifying failures caused by defects when the software is run. A defect can reside in a work product for a very long time without causing a failure. The path where the defect lies may be rarely exercised or hard to reach, so it will not be easy to construct and execute a dynamic test that encounters it. Static testing may be able to find the defect with much less effort. 
• Static testing can be used to improve the consistency and internal quality of work products, while dynamic testing typically focuses on externally visible behaviors.  
• Using static testing techniques to find defects and then fixing those defects promptly is almost always much cheaper for the organization than using dynamic.