Phased implementation is a method of changing from an existing system to a new one.

Phased implementation is a changeover process that takes place in stages. Think of a supermarket for example. Imagine that only the vegetable section is changed over to the new system while the rest carries on with the old. If the new system does not work properly, it won't matter too much because only a small part of the supermarket has been computerised. If it does work, staff can take turns working on the vegetables counters to get some practice using the new system. After the vegetables section is working perfectly, the meat section might be next, and so on. Eventually all the parts of the supermarket system would have been phased in and the whole thing would be running. This takes a long time and there are two systems working until the changeover is completed. However, the supermarket is never in danger of having to shut and the staff are all able to get plenty of training, so it is a much friendlier method.

Other methods of system changeover include Direct changeover

Direct changeover

Direct changeover is one of the methods to change from an existing system to a new one. This is the simplest methods of changeover. Imagine a new checkout system for a supermarket...

 and parallel running

Parallel running

Parallel running is one of the ways to change from an existing system to a new one.During changeover, a new system and an existing system run side by side. To input the same data and perform the same processes, compare their output and prove the reliability of the new system...

.