DELAY ANALYSIS TECHNIQUES-TIME IMPACT METHOD

The fourth method of delay analysis is called time impact analysis. This method attempts to determine the impact of delay events on the contractor's intentions for the remaining works, taking into account the actual progress at the time the delay event occurred. 

The first step is to verify the contractor's planned programme and correct any errors. The second step is to identify the delay events and periods. Next, the actual progress of the works at the start of the first delay event is input into the contractor's programme to check whether the completion would have been delayed by the contractor's rate of progress. Activities representing the delay are then added to the programme, which is then re-analysed, and any further delay is recorded. It is then argued that the further delay is the contractor's entitlement to an extension of time at the time the delay event occurred. The process is then repeated for each delay event.

Time impact analysis requires a suitable  planned programme that truly reflects the contractor's intentions for executing the work. This method also requires reliable and consistent progress data at small enough intervals to make the analysis meaningful.

When undertaken properly, this method of analysis addresses the complex issue of concurrent delays, acceleration and resequencing of activities. It is often used by expert witnesses when giving opinions in arbitration or litigation. It is also the method recommended by the Society of Construction Law's Delay and Disruption Protocol.

Due to its complexity, time impact analysis has two significant disadvantages: it can be slow and so expensive to carry out; and can be difficult to communicate the approach and results.

I think that there's no single method of delay analysis that will suit all situations. The choice of method of analysis depends upon the requirements of contract, nature of delay events, quality of planned programme, records to hand, time available, value of dispute and target audience.

If there were a single method of delay analysis that yielded one result from a given set of facts then there would be little doubt as to the party responsible for the delay. Until such a method is found, however, delay analysis will continue to be a subject of much debate.