Delay Analysis: What Is it? And What Do You Need to Know?

Founder of Chronos Consult, Tim Marlow specialises in delay analysis and has compiled reports on delay as an expert witness. Over the course of his career, Tim has been involved in  the preparation and critical path analysis of construction programmes, resource scheduling on construction projects throughout the UK and internationally. In this article, he discuss what you need to know about Delay Analysis.

Construction projects rarely run according to plan. Even the smallest of projects will experience change, and at some point, delay. Delay and disruption are repeatedly cited as key causes of cost escalation and disputes in industry reports.

Ideally, change will be managed to minimise cost escalation and reduce the likelihood of an issue escalating to a formal dispute. However, should an issue reach the point where it requires the decision of a third party, such as an arbitrator or adjudicator, then strong evidence will be needed for the demonstration of a claim.

In the case of a delay to progress or a delay to completion, evidence will often take the form of a delay analysis. The key is to establish a clear link between a cause of delay and the subsequent effect.

Establishing the Cause

An entire article could be (and has been)[1] written on this subject alone. However, establishing cause is key to demonstrating delay and its effect. It is crucial to identify the individual cause of any delay. This will also require evidence. It may be something simple, such as an instruction to stop work from the Employer or Engineer. However, it could be something less obvious or more difficult to identify, such as bad weather, poor management, or issues with supply chain.

Whatever the cause, it will be critical to identify the point at which the delay occurs, and its impact upon the programme.

Identifying the Effect

When approaching a dispute or claim, it will not be good enough to simply state that the project has been delayed by xx many days, therefore extra time or money should be made available for those days. Here, it is important to note that a delaying event may not impact the project at all. A delay to progress may affect an activity that no other part of the project is reliant upon, and is not, therefore, ‘critical’.

It is at this point, perhaps, that critical path analysis of delay should be mentioned. The critical path is described as, “the sequence of stages determining the minimum time needed for an operation, especially when analysed on a computer”.

Critical Path Analysis

Though it developed in the 1950s and 60s, critical path delay analysis has only really become common in the past two or three decades. Since the late 1990s, computer power has been such that it has been possible to use a desktop computer to carry out a very complex critical path analysis. There has therefore been an explosion in the use of critical path analysis to assess the impact of a delaying event on a construction project.

This has been particularly prominent in forensic delay analysis, where a project is analysed after it has been completed. Using the critical path analysis, the impact of a delay (or usually, multiple delays) upon the completion date of a project can be identified. The analysis can then be presented to a tribunal or decision maker as part of expert evidence.

From there, a decision can be reached on an allowance for additional time or money – depending upon what the contract for that particular project allows.

Methods of Analysis, and the Retrospective v Prospective Debate

There are many methods of analysis, and several of the recognised methods have multiple names. Add to this the fact that some people seem to get regularly confused about the different names, and the world of delay analysis can seem quite bewildering.

Some of the recognised methods include[2]:

  • As Planned v As Built
  • Time Impact Analysis
  • Impacted As Planned
  • Collapsed As Built

However, one of the biggest areas of debate lies around the ‘retrospective v prospective’ analysis. Should you analyse based on what happened? Or, should you analyse delay based on what the delaying event’s effect on a project is, at the point it occurred?

For a successful retrospective analysis, accurate and regularly updated progress records are essential. The analysis will look back at what happened and attempt to extrapolate the impact of delaying events from the as-built records and programme.

For a prospective analysis, it is important to have an accurate programme, but the analysis looks forward to identify what the likely impact on a project will be. However, a prospective analysis does not necessarily look at what actually happened in the past. This can present something of a conundrum on a project that has been completed, but which encountered delaying events.

What Does the Contract Say?

Another key point for the analysis of delay is to check what the contract says. Often the contract will say nothing, which can be helpful or unhelpful, depending on your point of view!

Interestingly, the NEC form of contract prescribes how delay should be assessed on a project. The contract (at Clause 63) requires the resolution of issues on a project as and when they occur.

There was a case a few years ago, however, in which that concept was challenged. In N I Housing Executive v Healthy Buildings (Ireland), the judge said, “why should I shut my eyes and grope in the dark when the material is available to show what work [Healthy Building] actually did and how much it cost them?” In other words, why guess what the outcome is likely to be if you know the outcome already?

Nevertheless, on reading industry literature and articles, opinion still seems very much divided on the best approach, particularly in the case of NEC contracts and analysis after project completion.

So What Should You Do?

Ultimately, the key is (as always) ensure you keep good records. If you find you do need to employ an expert to assess delay on your project, then good quality records will be key. An expert can help identify the best route, using the records and information available, but good records are essential. With good records, you can minimise the cost and maximise the likelihood of success in the event of any potential dispute.

And if you need assistance, get in touch with Chronos Consult today.

[1] For example:


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