What makes a good project schedule?

“I have a longstanding interest in project failure.” How’s that for an interview response? Seriously if you don’t understand why things go wrong, how can you be certain you won’t break them? We don’t know all the answers, but we know enough to recognise that project planning can play a significant part in determining outcomes and compared with many other contributory factors it is easier to identify and correct poor project plans.

Opinions on how to tell whether a schedule or project plan (hereafter referred to as a “schedule” for simplicity) is fit for purpose are as many and varied as planners themselves and that’s always been part of the problem. The need for a schedule at all is frequently seen as a tedious contractual imposition, another box to be ticked, whilst the people who know what they are doing actually deliver the project. In fact, if it’s not formally required, the traditional back of a cigarette packet may be as good as it gets. No wonder that project planning is often not treated as a professional discipline, but a pseudo-science like fortune telling and that there may no appetite to ensure that the schedule is fit for purpose.

Such carelessness may be heavily punished in the commercial disputes that inevitably follows time and cost overruns, but that’s another story. For now, let’s assume that an ounce of prevention is worth a pound of cure a schedule should be continuously checked against three holistic criteria:

  • Content
  • Technique
  • Clarity


“Does this schedule represent a meaningful, realistic view of project execution?”

If the schedule isn’t appropriate to the nature of the project or it is obviously unachievable then it is not realistic. If it doesn’t include everything that is in scope then it is not ­meaningful. This is known as the 100% Rule. The Work Breakdown Structure (WBS) has to include 100% of the work defined by the project scope and capture all deliverables.

These are points of failure for the shy and inexperienced because it is necessary to identify what the entire scope is and determine how and when it will be delivered. Generalist planners need to pick the brains of their project team colleagues. Specialist planners, may know their sector so well that they can effortlessly clone suitable work packages, but the best of them will still engage with their colleagues too.

 “Plan the work, then work the plan”, is not a mandate for planners to take charge, it’s a mantra for the whole team. Failure to consult colleagues rarely ends well for the planner and the most meaningful and realistic schedules are produced by planners who are facilitators who can ensure that it is “our plan, not my plan”. Of course, this requires time and patience, which may be limited in the early stages of a project when first schedules need to be agreed against uncompromising deadlines, but beware those tempting shortcuts that may be cul-de-sacs.

Garbage in, garbage out!


We don’t believe that a planner needs to be an outright software jockey. Of course a good planner must be able to navigate their planning tool of choice and, ideally understand infrequently used features that can be useful, but what they really need to know is how to construct a schedule to a standard that means it functions properly.

There are recognisable deficiencies that can seriously undermine a schedule, for example open ended activities and excessive constraints are pitfalls known to most planners and they are easily detected, but there are other more nuanced dangers such as lack of detail and excessive use of constraints or lags that will make a schedule ineffective, harder to understand, harder to maintain and ultimately less credible to third parties. The most obvious consequence of poor schedule quality is a schedule that cannot be relied upon for good or bad news.

Don’t neglect schedule quality just because it may seem tedious. Software has emerged in recent years that is so fast and effective that there is no excuse for a badly constructed schedule. Well almost no excuse, quality comes at a price, as our annual Acumen Fuse renewals remind us. However, if you struggle to justify software you’ll only use occasionally, then ask us to do checks for you, we’ve invested in licenses so that you don’t have to and we really do know about schedule quality.

If a good quality schedule is no guarantee of a successful project, consider the contrary!


So vital, yet so easily overlooked. Whatever else a schedule may be, however skilfully it has been crafted, if it can’t communicate, then it fails.

Planners may believe that because they built the schedule, they’ll always understand it, but it’s a dangerous presumption. No planner is indispensable, in fact I’d take such a claim as a sign of project risk management missing a single point of failure. A schedule needs to be clear enough that any reasonably competent planner can understand it; better still it if it is comprehensible to non-planners too.

A Schedule Narrative provides clarity and is often a mandatory contractual requirement in its own right. It’s a user guide covering the strategy and assumptions for the project execution which also identifies and explains resourcing, sequencing, use of constraints, critical path, risks, exclusions, exceptions, external interfaces, calendars, etc.

The schedule itself should be self-explanatory with consistent meaningful naming conventions. These are often contentious even within the same team, for example some people prefer long descriptive names whilst others demand brevity. Even with many correct but diverse answers there are still some indisputable elements of good practice, for example deliverable Work Packages should be described by nouns and Activities by verbs. However, a thousand Activities that are each called “doing something” makes no sense unless they can be differentiated from each other in a way that is both obvious and consistent.

Make use of available user variables (UDFs/Custom Fields/Activity Codes/Notebooks/etc) too to explain, describe and categorise schedule data.

Know what you want to say, know who you’re talking to!


We’ve barely touched on what makes a good schedule, but perhaps shown that a holistic approach based on three criteria is a promising start. 

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