The establishment of a reasoned ‘plan' of how works are to be carried out can be fundamental to the success of any project. The representation of the 'plan' is often in the form of a programme. However, events can arise that result in project delays. These delays may influence activities on the programme, resulting in them taking longer than originally planned or even carried out in a different sequence. New activities or tasks may be introduced into the programme.

The aim of delay analysis is to investigate the impact of delay events upon the project. This analysis may involve various procedures and selection of the appropriate procedure will often depend upon the circumstances in each particular project. The type of analysis may be dependent upon the available information.

DELAY ANALYSIS
Delay analysis can include scheduling (ie, planning or programming) methods which require considerable mathematical processing capabilities; these days nearly always involving computers. However, there will also be a requirement for knowledge-based decisions, in terms of construction methods and programming techniques, such that the basis for the analysis is reasonable.

The terminology adopted for types of delay analysis vary. In the brief descriptions below, contractual frights' are not considered and the procedure alone is summarised.

AS PLANNED/ENTITLEMENT METHOD
In adopting this simple approach, the programme for the project is taken as 'gospel', in that the activity durations, timing and logic are assumed as being correct. The delaying event is introduced into the programme and the 'result' (or consequence) is found by rescheduling the programme to establish if there is a revised completion date. This relatively simplistic approach may give the answer that is wanted by the party delayed. It may not stand up to scrutiny in regard to being a reflection of obligations and reality.

'AS BUILT' PROGRAMME ANALYSIS
The analysis relies upon a programme of how the works were actually constructed and this is usually overlaid on the intended plan of works. If not available as a contemporaneous record, the asbuilt programme would be built up from available records. The programme so produced does not demonstrate the reason for delay, rather this would flow from investigations of any variances from the intended plan.

IMPACT ANALYSIS
Impact analysis can fall under a number of headings and can be utilised in different forms. Terminology such as 'update impact schedule analysis' or 'time slicing' are used as are 'simulated as-built analyses' and 'but for' and ‘snapshot' analysis. However, the principle is that detailed analysis is carried out using a step by step approach. The approach requires that all circumstances at a point in time or at the occurrence of a particular event be recognised. Having recognised the conditions at the time of the event, if there is a change from the position originally envisaged, this must be established, and reflected in the next step of the analysis.

The programme through to completion must be established utilising this information. The impact of events can be assessed by analysing if and how the change affects the programme to completion.

The analysis will reflect the circumstances at the time of the event in question and it can be this consequence which is then asserted as being the effect of the event. Analysis may be carried out at periods through the project such that a 'time slice' picture is built up. This 'time slicing' will allow recognition to some extent of the dynamic nature of project work.

PRODUCTIVITY ANALYSIS
In using impact analysis, the basis of the delaying event may be productivity levels rather than periods of delay. The analysis will utilise the anticipated productivity and actual productivity as the basis for the analysis.

In future articles, 1 will give detailed examples of using delay analysis methodologies.

Roger Smith is an Associate Director (Planning) Trett Consulting Manchester office.