PPT Slide
Therefore, by adding more MAN-MONTHS, we are, in fact, increasing the completion time of the software project because the communication is going to affect the completion time of the project.
Thus, the assumption that MAN and MONTH are interchangeable is not correct.
Another very important factor that affects our estimation of completion time of software projects is the system testing and debugging process.
Brooks' rule of thumb for estimating the completion time of software projects:
- 1/3 time for planning;
- 1/6 time for coding;
- 1/4 time for component tests;
- 1/4 time for system test with all components in hand.
Note that the testing and debugging takes about 50% of the time, while coding, which people often worry about, only takes about 1/6 of the time.
Actually, coding is the easiest phase to accurately estimate!
Underestimating the time it takes for system testing can become very dangerous because it comes at the end of the project:
- project is already fully funded and has the most manpower allocated to it,