Glass law states that “requirement deficiencies are the prime source of project failure “. It says that reaching all the requirements of a project should be the first thing to prefer for completing the project successfully. After his research on several failed projects and going through many projects he stated the above law on project failures. For a successful project to be completed setting the goals correctly should be a demanding task .The common error is due to humans and can be illustrated due to lack of communication between customer and analyst or software . Example:
For example a car with 1 or 2 persons in it ,the air pressure in the tyres is less and volume is more and the same car filled with luggage and 6 to 8 persons the air pressure is more in tyres and volume is less . BOEHM’S FIRST LAW:
Boehm’s first law states that “Errors are most frequent during the requirements and design activities and are the more expensive the later they are removed”. He says errors are made generally while collecting the requirements and developing the project. Most errors occur in early phase of the project which may be the design errors or the requirements.
Questions arise when analysing those errors and putting some extra work can change the phase of the project and if the developer does not know the domain, the project will fail. The cost purely depends on the time. The early it’s removed lower the cost. Example:
For example a study done at TRW in 1974, the errors in design stage was 64 percent where as coding errors account to 36 percent and also 54 percent of errors were not found earlier than acceptance testing. This stated that Design errors took twice as much time to diagnose and correct than coding errors. BOEHM’S SECOND LAW:
Boehm’s second law states that “Prototyping (significantly) reduces requirements and design errors, especially for user interfaces”.