Successful Project Forecasting: How to do it in 3 simple steps

Being able to successfully forecast project timelines is a skill that will always put you on the path to successful project delivery.

I’ve written before about the Top 5 Issues with Project Forecasting. But eliminating forecasting issues is only part of the answer. So, in this article, I’m going to share my three simple steps for getting project forecasting right from the very start.

Choosing a forecasting strategy

Before I get into my simple steps for project forecasting, we need to talk about the way you should approach forecasting with your project team and stakeholders.

Typically, there are four ways project timelines are set.

  1. The leadership team or senior expert defines the timeline.
  2. Each team member defines the time estimate for their activities with the project leader.
  3. Each team member defines the time estimate for their activities with the rest of the team. Forecasts are discussed, challenged and agreed as a collective.
  4. Each team member defines the time estimate for their activities with the rest of the team and key stakeholders. Forecasts are discussed, challenged and agreed as a collective.


In my view, the above list is in order of least effective to most effective when it comes to deciding project timelines.

While option #4 is what I would always recommend as the most reliable strategy, however you choose to define the timeline for your project, it’s the information you use to decide the timelines that is the most important part of the process.

And this is where the three steps to successful project forecasting come in.


Step #1: Be clear on the Project Strategy

The first and most valuable place to start in your timeline planning is with the project strategy.

The project strategy is made up of the project ‘why’ and the delivery approach. The ‘why’ outlines the need or pain point you must satisfy, and the approach is the path you’re going to take to deliver the project.

In my article How to deliver a successful project with good project strategy, I talk about how the ‘why’ is the anchor that should underpin all project decisions. When you know the ‘why’, you’re more likely to select a delivery approach that is less disruptive to your stakeholders and more engaging to their needs.

I often see teams provided with a project scope, without a clear understanding of how the scope links back to and satisfies the strategy.


Tip: Beware assumptions

When projects are not truly clear on the ‘why’, they tend to make more assumptions about what is and isn’t important. This causes project teams to make poor decisions on behalf of their stakeholders.

Assumptions lead to disengaged stakeholders, unfit-for-purpose or incomplete solutions, re-work, and an increased risk to project deliverables.

They also lead to an increase in un-forecasted time being spent making a course correction, which will conflict the team and challenge your priorities.

This will be the start of your time management seam beginning to unravel.

Whether the strategy was set with your input or not, it’s still your responsibility to know it.

And if that means asking and questioning, then that’s what you do – particularly if you foresee a problem. If the question has already been considered and it’s not a problem – good on you for caring enough to check! If it hadn’t been considered and you discovered and helped mitigate a risk – outstanding work! Asking the question is always a win-win!

Step #2: Understand & Document Project Scope

When it comes to successful project forecasting, a huge part of your success will always come down to clarity of scope.

The project scope will detail all the tasks needed to satisfy the ‘why’. It’s where the bulk of your project deliver time will be spent. And if you don’t satisfy the why, then you can’t deliver your project.

So, how do you make sure you’re clear on scope?

Start by seeking out any dependencies which impact the scope or timeline restrictions you may need to consider.

Estimating time for the things we know, is fairly straightforward, provided you have access to the experts who understand the subject area and you’re given the information to questions you ask.

The challenges occur when we are expected to forecast for things we haven’t entirely decided, don’t fully understand, or have never done before.

Something I always tell my project teams is that you should only ever scope the things you know. The scope is what you commit to delivering. If you don’t have clarity over your scope item because you don’t have enough information, then you can’t be sure if you can deliver on the scope and therefore meet your commitment. And from a timeline perspective, you can’t accurately forecast a timeline.

Tip: Beware assumptions

Anything that is unknown should be scoped as a discovery task. This will give you the opportunity to determine what to do, how to do it, and who to involve. Once this information is known, it can be added to your scope and a timeline can be forecasted.

Step #3: Know WHO you need to help you deliver

This step is all about understanding WHO you’ll need access to, both for information AND for resourcing.

When you have an idea of who you will need to engage, you can start to consider how much time you will need from each stakeholder, how easily you can loan their time to gather information or how difficult this may be.

For example, senior leaders may not be accessible as regularly as other stakeholders and you might also require a much longer lead time to meet with them. Other stakeholders may be hard to reach at specific times of the month or day such as financial month end reporting times.

Another consideration are times people are unavailable. This can include part-time employees, public holidays, leave, or system shutdowns.

Understanding when your key stakeholders are and are not available will help you to consider how much time needs to be allocated for consultation and information gathering.

Let’s start project forecasting

If Now that you know the:

  • Project Strategy
  • Project Scope and
  • The Who,

you can work together with your team and key stakeholders to detail time estimates for each task.

Working together gives people a chance to raise and address concerns as a group, answer questions, and provide information which may result in a more accurate estimate.

One final project forecasting tip – Contingency.

No matter the size or length of your project, you should estimate some extra time before the project’s hard end date.

As part of your planning, you will quickly realise that all projects carry risk. When risks turn into issues, some have no impact on the timelines while others will cause delays. Having already allowed time in your project schedule to absorb these delays means you’re more likely to track to your project commitments and meet delivery deadlines.

How much contingency should you allow?

If you’re a new team or delivering for a new client, you may want to add an additional 10-20% buffer to the time forecast of each milestone. This will allow for learning the cadence of the team’s delivery as well as the engagement from your stakeholders.

Depending on the length of your project, and particularly for a longer project, you may choose to keep this buffer for the entire project or remove it once you feel you have more confidence in the team’s forecasting.

Project Strategy, Project Scope, Project People

These are the three simple steps you need to follow if you want to be able to successfully forecast a realistic timeline for your project.

And like all things, the more you DO, the better you’ll get. So, make sure you put the three steps into practice on each and every project you’re tasked to deliver.

Want a complete guide to Project Planning & Delivery? Meet the PWP Project Manifesto.

Don’t let scope creep, incomplete user requirements, poor stakeholder engagement, or post-delivery defects de-value your project!

The PWP Project Manifesto is the structure of a business requirement document, the detail of a scope document and the guidance of a support coach all rolled into one.

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