The systems analysis team will not always recommend that a new system be developed. This will largely be a cost-benefit decision. Basically a series of designs of increasing resolution are developed, until a detailed specification of the new system is produced. Once approved the system is ready for implementation. Now the nuts and bolts are put in.
Computer programmers convert the final program plan into computer code.
Source documents are constructed and printed. It may take a long time to write, debug and successfully interface a new computer program, particularly if compatability with old data files is required. Training in the new system is conducted during this phase. Finally, the system conversion activity involves the changeover of data processing from the old to the new. Often there will be an overlap period under which dual processing occurs.