A computer system consists of the hardware, the software, the data, the people and the ways they all interact.

When a company needs a computerised solution to a problem, they call on a systems analyst to oversee the 

• analysis,
• design, 
• development, 
• testing and 
• implementation 

....of a new computer system....and possible further maintenance....

More correctly....

........systems analysis involves a detailed study of an existing system and requirements of a new system...

........and systems design involves the design of the new system (hardware, software, data and people)

One of the jobs of the systems analyst is to make sure the new system is...

....cost-effective - the new system should generate more money than is spent on installing and running the new system!

....completed on time

....completed within a budget agreed with the management of the company.