The management have taken the decision to proceed with the project.

The next phase is called the 'Investigation and Analysis' phase.

First you define how the old system works (investigation) and the problem(s) it is causing.

This is done by a variety of techniques that include:

The investigation part confirms that the true cause of the problem has been correctly defined.

It also confirms that the project will overcome the problem.

The next part is to carefully analyse how the existing system works: Not necessarily the hardware or software - but more about how information is handled and how people interact with it.

As all this needs to be communicated efficiently to all concerned, a number of standard diagrams / methods are used.

System diagrams:

These show the relationships between the various systems in the company (or even outside if relevant) - how they interact, what depends on what and so on.

Data Flow Diagrams:

Most systems deal with information in one way or another. What really matters is how the information flows through the system. How does it branch and re-join. What outputs are created and so on.

The 'data flow' diagram seeks to show this movement through the system.

Process diagrams:

People handle information in a specific way - they have a 'process'. For example, an employee makes an expense claim. First of all their manager counter-signs the claim. It then goes to the account manager who authorises payment and so on...This is 'process flow' in action.

Process diagrams try to show how people interact with the system - who and when (and why).