Without proper change control and scope management on the project, several things are likely to suffer including profitability, on time delivery and customer satisfaction.
Change control is one of those tasks the project manager must do but usually hates to perform. It's never easy. It can require an iron fist mentality and the willingness to take a hard line with the very customer you are trying to satisfy. Sort of a Catch 22. It can result in increased revenue, but always at the expense of a customer that needs the change to meet a business process need or requirements clarification. It can increase project profitability, but only if you are very accurate in your effort planning and estimation because it can quickly decrease project profitability. It will almost always result in a longer implementation time because more work is required – not that you're missing a deadline because the work is required, but it will always feel like you're missing a deadline. You can win, but it often feels like you're losing, too.
Delivering the right solution.
Without proper change control and scope management in place, we run the risk of delivering the wrong solution. How? Because if the customer requirements call for 'x' and we allow that to morph into 'y' because of small changes the customer may think are good then when it comes time to test, the solution being tested won't match the requirements. And if no change orders were drawn up to cover the small changes requested by the client, there is no trail to test against. So which is really right – the requirements or or the solution that is being tested but doesn't match the requirements? And does anyone really know?
If those changes are made – and if they are the right ones, then the solution being tested is right. But because no changes were tracked via scope management and change orders, additional project revenue was not realized for that work and timeframes weren't extended due to the extra tasks happening to make that work possible. What suffers then? Profitability. You still did the work, but you didn't add revenue and therefore those costs associated with the work just hit the project budget without bringing any further euros with it. Added cost without added revenue equals decreased project profitability.
Staying on schedule.
The same holds true for schedule. Adding tasks to do the work, but not adding any time to the project schedule as a result of a change order, means you'll get the work done but you won't likely be able to deliver the project on schedule. Especially not if you need to test adequately and do everything you planned to do on the project. Those tasks that were added to do the out of scope work have to hit somewhere and the timeline takes a hit with those activities.
Minimizing change orders.
Good change control means you can bring potential changes up to the project client as they become obvious. Good scope discussion with your project customer will result in wise change order decisions on what we should allow to affect the project and what isn't really necessary. If they client knows what is a change and what isn't – because you're doing a good job managing scope – then they can make wise choices on potential changes. Some are going to obviously be necessary...some will be deemed luxuries and tossed aside.
It's never fun to be the one who has to yell “out of scope!” to the client and come running with an expensive change order to sign. Just like it's not fun to be the parent who does most of the disciplining in the family. But it has to be done or you'll soon have a mess on your hands.