Every project - small or large - has at its root an idea, a vision of how things ought to end up at its completion. However, the project will develop a great deal after that original intent is formed, and it may be drawn in a different direction; as the plans continue apace, the nature of the proposed outcome may change substantially. Of course, the new vision may be rather better than in its predecessor - it might be bigger and bolder, it might be more efficient and precise in its aims - but it's always essential for the project manager to understand the impact of the changes upon schedules and budgets, and indeed on the viability of other aspects of the plan. Without careful control of the project, its scope can creep out in new directions that might potentially derail the entire venture.

The veteran broadcaster and diarist Burton Mandleby has been signed up by Lambton Network Productions to host a series of travelogues, making his way by every available means of transport from the far north of the Americas all the way down to Cape Horn. Lambton have entrusted Bradley with the weighty task of producing the show - production, in television and film, being the key managerial role on a project, the individual ultimately in charge of looking after the non-creative aspects of the process. And for Bradley, the issue of scope creep is a major one: the range of locations that Mandleby and the crew could visit is enormous, whilst the budget and schedule are strictly limited. How can he be sure that those limits will be rigorously adhered to, without jeopardising the artistic integrity and quality of the programme?

The first step is to form a clear and precise plan, one that covers every detail. In stating unequivocally and from the outset what will be done, it's much easier to turn down the temptation of expansion. After all, squeezing the whole of the Americas into eight half-hour episodes guarantees a lot will be missing, and this in turn ensures requests will be made to include this city or that landmark; it'll be easier for Bradley to stand his ground if he knows and can explain exactly what that ground is and how it fits in with the budget and schedule.

However, it's important for Bradley to be able to consider any suggestion on its own merits. Coming up with that clear and precise plan from the beginning is important, but neither clarity nor precision assures perfection, and new ideas that come Bradley's way may be beneficial. Perhaps there'll be a suggestion for a new audience-pleasing segment in the first episode that will keep viewers tuning in for the rest of the series, or a very dramatic scene that can be heavily featured in the trailers - there would be no advantage in sticking stubbornly to the original plan if a new revision would make the project more successful. The key, then, is to pick the changes that are worth including out of those that aren't.

Easier said than done? It might seem that way, given that there isn't an absolute, black or white distinction between good ideas and bad idea. But it becomes much simpler for Bradley to select the useful changes by looking at them through the lenses of two important principles.

First of these is the Pareto principle, the balance between effort and benefit; in deciding whether to adopt an alteration, Bradley should look for the greatest advantage from the least amount of work and money expended.

Secondly, he needs to weigh up the impact of a change upon the rest of the process. In any project, bringing resources into a new addition to the plan can cause a shortfall of resources elsewhere, potentially causing harmful delays to the critical path; in this specific case, the critical path can be seen in very physical terms, a journey from one end of a continent to the other, and every deviation to the route must necessarily have an impact on cost and time.

Bringing these two assessments together, Bradley can look for changes which bring more than they take, which adhere closely to the established proposals and offer a more effort-efficient benefit than the existing tasks - in other words, incorporating stops along the route that are more attractive to viewers than the original plan, while ignoring changes that drag presenter and crew into an expensive detour for no good reason.

Ultimately, resisting scope creep isn't just a matter of Bradley sticking religiously to his original plan, but of him knowing when alterations to that plan will enhance it - and being confident enough to reject suggestions that won't help. The latter may often be difficult, particularly if there's significant pressure - perhaps from a senior manager or stakeholder - to include a certain change, but with a thorough understanding of the impact of a particular addition on the overall project, he'll find easier to stand his ground and state his case persuasively for doing so. And when Bradley faces such pressure, knowing that he can produce clear evidence of how his current plans make the best use of time and money (and how the proposed change would impact upon this) gives him the confidence to say no to harmful scope creep.

Whatever project your organisation is embarking on, whatever the size and aims, it's vital to differentiate between useful additions to the original plan, and changes that will only produce the scope creep that can knock a hole through budgets and schedules - or derail the process entirely. Certainly, it's worth considering a short training course for yourself or your staff to help develop or enrich this essential skill, bringing advantages to any project and to the company as a whole. Recognising positive amendments can bring about a much enhanced end result, whilst cutting out scope creep can help the established plans run far more smoothly and successfully; given such benefits come from controlling change, there's no reason to put up with the alternative.