Measuring Delay Using the Contemporaneous Period Analysis

Over the years, analysts have used a number of different analysis techniques to identify and measure project delays.  Many of those techniques required the analyst to abandon or alter the schedules used by the project participants to manage the project, ignoring much of the contemporaneous information contained in the schedules.  To prevent the loss of this important data and to avoid substituting the analyst’s potentially biased perspective for the perceptions and actions of the parties managing the contract work when the delay was actually experienced, the Contemporaneous Period Analysis (CPA) technique relies on the project schedules and the contemporaneous project documentation (known as as-built data) to identify and measure critical project delays.  

The Observational Contemporaneous Period Analysis

This paper will focus on the Observational Contemporaneous Period Analysis (OCPA), which is a form of the CPA.  The term “observational” means that the analytical technique does not require the after-the-fact creation of a separate or special schedule, the insertion of fragnets or “impacts,” or any other revisions to the project schedules.  In other words, the analysis is based on the “observation” of the schedules that existed on the project at the time of the delay – the “contemporaneous” schedules.  “Period” simply means that the analysis is typically organized and performed in discreet periods, the time between the schedule updates.  The analysis is typically performed chronologically from schedule update to schedule update.  This presentation technique, however, should not be confused with the windows in a “Windows” analysis.  The OCPA is also known as the “Contemporaneous Schedule Analysis.”  


Why Use the Contemporaneous Project Schedules?

The OCPA begins with the baseline or as-planned schedule, typically the earliest complete and approved project schedule.  Typically, as of the data date of this schedule, no project work has been performed.  Consequently, the baseline or as-planned schedule depicts the project team’s original plan to construct the project and often serves as the starting point for the analysis of critical project delays.  Starting with the as-planned schedule, the analysis proceeds chronologically to the first schedule update, and then proceeds update to update to the project completion date.  The analysis moves chronologically through the project, tracking progress on a daily basis and measuring delays and savings to the critical path and project milestones.  

The contemporaneous schedule updates serve as snap-shots of the project’s status at specific moments in time.  As snap-shots in time, the schedule updates identify the actual start and finish dates of the schedule activities, the progress achieved on activities that have started and not finished, and the actual sequence or logic of construction.  These updates also capture revisions made to the schedule as the project evolves to address the actual circumstances encountered.  

By way of analogy, the baseline schedule represents the original route or plan that will get you to your destination or to project completion, hopefully depicting the quickest and most efficient way to get there.  The schedule updates can be characterized as pit-stops along the way, allowing you to evaluate where you are, what you did to get there, how long it took, and ultimately what it will take for you to arrive at your destination on time.  In many cases, you will make adjustments or corrections to your route, path, or plan during these pit-stops after evaluating your progress.  Perhaps you encountered more traffic than expected that slowed your progress or some key materials were delivered late and you had to change your plan to compensate; either way the schedule updates provide both the contractor and owner with the most current route or plan to complete the project.  It does not matter whether the plan depicted in a schedule update is the same as the original, slightly different, or drastically changed, as long as the schedules represent the project team’s plan to finish the project, they should be used in the analysis.  Over the course of the project, as the contractor modifies its means and methods in response to changing project conditions and changes in activity durations and logic relationships, those changes are integrated and captured in the schedule updates.  Therefore, as the OCPA proceeds chronologically from schedule update to schedule update, relying on the contemporaneous schedules, the analysis assimilates the project team’s changing plan.  This incorporation of the project team’s evolving plan for completing the project is one of the strengths of the OCPA technique.  This strength and others will be addressed in more detail in the next section of this paper.

Strengths of the OCPA Technique

The OCPA technique has a number of strengths that make it an exceptional tool for identifying and measuring critical project delays.  

Contemporaneous/Real-Time Perspective

One strength of the technique is its contemporaneous/real-time perspective on the project schedule.  The OCPA technique is founded on the premise that the contemporaneous project documents – the documents used by the project participants to manage the project – are the most objective and least biased source of information concerning the status of the project at any point in time on the project.  Therefore, using the contemporaneous project schedules to analyze critical delays chronologically through the project, the OCPA forces the analyst to analyze the project delays in the same order and at the same time during construction of the project as the project participants did.  The analyst is essentially sitting in the shoes of the project’s managers and evaluating the merits of the decisions made by them using the same information that was available to them.

There is a substantial and mounting body of case law that confirms the wisdom of the OCPA approach.  The Veterans Administration Board of Contract Appeals may have said it best:  “…in the absence of compelling evidence of actual errors in the CPM’s, we will let the parties ‘live or die’ by the CPM applicable to the relevant time frames.” VABCA No. 2168, 87-3 BCA (1987).

Specifically Identifies Delaying Work Activity

Another strength, and perhaps its most useful attribute, is the technique’s ability to assign delay or savings to a specific item of work.  As the technique tracks progress along the critical path on a daily basis and measures the effect of that progress to project completion, the analyst can easily identify the work activity responsible for the delay or savings.  This specific allocation of delay enables the analyst to better evaluate and assess responsibility for the delay to the correct party.

Addresses the Complexities of CPM Scheduling

An additional strength of the technique is that it addresses and accounts for the complexities of CPM scheduling.  The technique can identify delays or savings as they occur, account for out-of-sequence progress, and identify shifts in the critical path.  

Because this technique analyzes project performance on a daily basis, it tracks the performance of specific work items on the critical path and measures the effect of this performance on project completion.  For example, if Activity A is the initial activity on the critical path and is planned to finish on day 5, but actually finishes on day 7, the OCPA analysis would show an equivalent 2-day delay to project completion.

Additionally, using the same example where Activity A finishes two days late on day 7, its successor on the critical path, Activity B, which is planned to start when Activity A finishes, actually starts on day 6 and makes two days of progress by the time Activity A finishes on day 7.  Given these facts, the analysis would assign two days of delay to Activity A and assign two days of out-of-sequence progress or savings to Activity B.  The net result would be no delay or savings to project completion.  This specific identification and allocation of delay and savings is necessary because different parties may be responsible for late finish of Activity A and early start of Activity B.

Lastly, tracking project performance on a daily basis enables the OCPA technique to identify shifts in the critical path and properly allocate delay and savings to work activities that are truly on the critical path.  For example, the technique identifies shifts in the critical path the following way.  Assume that Activity A is the initial activity on the critical path and has zero float, and Activity C has 2 days of positive float and is not on the critical path.  Over the course of the next week Activity A makes expected progress and Activity C makes no progress.  During the week, due to its lack of progress, the float of Activity C will decrease one day for every day that it does not progress, causing its float to decrease to zero and ultimately become negative.  At some point during the week, when the float of Activity C equals Activity A and then becomes negative the critical path will shift from Activity A to Activity C.

It should be noted that in complicated CPM schedules with multiple calendars changing total float values will not always identify shifts in the critical path.

Self-Correcting Analysis

The OCPA technique is also self-correcting.  This technique accounts for and identifies missing activities and missing logic relationships as it moves chronologically through the project from schedule update to schedule update.  Because it tracks progress on a daily basis, it will identify gaps or periods of no work that exist along the critical path between existing work activities.  These gaps could represent schedule’s missing activities or logic relationships.

For example, if two activities on the critical path, Activity A and Activity C, were linked with a finish-to-start relationship and Activity A finishes, then Activity C should begin the following day.  However, if the schedule is missing an activity, Activity B, that falls logically between Activity A and Activity C, then the analysis would depict the existence of the missing activity as a gap.  No critical work would be performed between the finish of Activity A and the start of Activity C.  In this way, the OCPA analysis technique “corrects” for the schedule error associated with leaving out Activity B.

The analysis accounts for missing logic relationships in a similar way.  For example, if there are two activities, Activity A and Activity B that are missing a finish-to-start logic relationship, the analysis will show that Activity B would only be able to begin once Activity A has been completed.  The analyst would then be able to identify that there should have been a logic relationship where the schedule did not have one.

Real-time Versus After-the-fact Application

Lastly, unlike many delay analysis techniques, the OCPA approach is both a real-time claims avoidance tool and technique that can be used at the end of the project, well after the delay has occurred.  The technique’s reliance on the contemporaneous project schedules provides the analyst with the flexibility to identify and measure critical project delay both during and after completion of the project.  

The reason the OCPA technique can be used both on a real-time basis and after-the-fact is because the analysis is performed using contemporaneous project records, not schedules prepared after the project work is completed.  It also does not rely on the preparation of “fragnets” or other tools to allow the delay to be discerned and measured.  As the analysis moves forward in time, it encounters and deals with the project’s issues and problems as they arise at the same moments as the project participants encountered them.


Requirements to Use the OCPA

In order for the OCPA to be a valid and reliable analysis technique, there must be contemporaneous project schedules that represent the significant aspects of the contractor’s planned construction sequence at periodic intervals during the project duration.  The analyst should review the schedules and establish that the project participants used them to plan and construct the project.  

Application of the Observational Contemporaneous Period Analysis
 
After the analyst has determined that the contemporaneous project schedules are reliable tools with which to identify and measure critical project delay, the analyst must apply the OCPA technique correctly to ensure the accuracy and objectivity of the results.

As mentioned earlier, the OCPA analysis is performed in “periods,” the time between schedule updates, and the proper application of the OCPA requires that each “period” be analyzed separately and in two distinct steps.

The first step of the analysis tracks the project’s progress on a daily basis from one schedule update to the next.  By tracking the critical path’s progress on a daily basis, the analyst will be able to identify and measure project delays or savings resulting from progress or the lack of progress and assign it to the proper critical activity.

    The second step of the analysis consists of identifying and measuring the project delay or savings that occurred when the schedule was updated.  In order to accurately differentiate between the delays or savings resulting from the project’s progress and schedule changes when the schedule is updated, the analyst should perform the analysis in steps.  This separation is necessary because the effect of the project’s progress on project completion can be measured and assigned to a specific work activity on a daily basis.  Whereas, the effect of schedule changes, which include but are not limited to logic changes, the addition or deletion of activities, revisions to activity durations, etc., should, in most instances, be evaluated at the moment in time when the schedule was changed.  This typically coincides with the data date or status date of the schedule update.

Identifying the Critical Path

In order to identify critical project delays, the analyst must first identify the critical path, because only delays along the critical path can delay the project.  AACE defines the critical path as, “the longest time path through the network,” and further states that, “if time to complete one or more jobs in the critical path increases, the total production time increases.”  Essentially, the critical path is the longest path of work through the project.  

In some instances, the critical path is easily identified because it is the zero total float path of work.  However, for more complex schedules, with varying float values, the critical path can be difficult to discern.  In some instances, the scheduling software can provide tools to determine the critical or longest path.  As an example, Primavera products provide a Longest Path filter that assists the user in identifying the critical path of the project.

First Step

The first step in the analysis is to measure the effect of progress to the project’s completion.  This is done by tracking the progress along the critical path chronologically each and every day, starting at the data date of the first project schedule and ending at the data date of the subsequent schedule update.  

Tracking the progress along the critical path each day will enable the analyst to assign critical project delay or savings to a discrete, critical work activity.  This critical work activity is usually the initial activity on the critical path.  The assignment of delay or savings on a particular day to the controlling critical activity is dictated by the effect of its progress on project completion.  The assignment of delay or savings to a particular work activity allows the analyst to determine more easily the responsibility for the delay at a later time.

By tracking the critical path on a daily basis, the analyst will also be able to identify when the critical path shifts and identify the new controlling critical activity and new critical work path.  This is a perfect example of how the OCPA technique takes advantage of the dynamic nature of CPM schedules and uses the inherent strengths of CPM scheduling to identify and measure the delays and savings to project completion.

The analyst can calculate the critical project delay or savings attributable to a specific critical activity by comparing its planned start or finish dates to its actual start or finish dates.  The difference between the critical activity’s planned and actual dates will extend, shorten, or not affect the length of the critical path.  Comparing the length of the critical path before and after the comparison will determine the effect of performance (or lack of it) of the activity on the project completion date.

When performing the analysis between two schedules, the analyst should use the earlier of the two project schedules as the basis for identifying and measuring delay or savings during the first step.  The first or earlier of the two schedules should be used in step one, because the analyst is essentially determining the project participants’ ability to meet or exceed the expected durations of activities identified in the current plan, which happens to be the first project schedule until the analysis reaches the second schedule update.

As the analysis moves chronologically through the “period,” or time between the schedules, and tracks the critical path on a daily basis, this first step is complete when the analyst has progressed the first schedule up to the same moment in time as the latter schedule and incorporated the same as-built activity information as in the second schedule.  Once this has been completed, the analyst then is able to identify the magnitude of the delay or savings that the project has experienced during the update “period,” by comparing the fully-progressed first schedule with original first schedule.
 
Verification of As-built Dates in the Contemporaneous Schedules

The analyst should use the as-built information contained in the contemporaneous project schedules.  In addition, the analyst should rely upon other contemporaneous project documents to support and validate the as-built dates (actual start and finish dates) in the schedule by referencing documents such as daily inspector reports and contractor daily job reports.    

When the as-built information is incomplete and does not allow the analyst to identify the date that work on a particular activity actually occurs, the analyst must decide how to distribute the progress shown between updates.  This distribution of progress within the activity’s actual duration is subject to differing interpretations and applications.  

For example, assume Activity A had a remaining duration of 10 in the first update and a remaining duration of 5 in second update.  If there were no contemporaneous documents to identify when those 5 workdays of progress were accomplished between the first and second update, then the analyst would have to decide when and how to show the work occurring on Activity A between the updates.  The analyst could assume that Activity A made 5 workdays of progress during the first 5 workdays after the first update, during the last 5 workdays before the second update, or in some other fashion between the updates.  Regardless of which method is chosen to distribute progress between the activity’s actual start and finish, the analyst should consistently apply the chosen method throughout the entire analysis and be able to explain why the method was chosen.

Corrections to the Schedules

In some instances, the actual start and finish dates contained in the project schedules will be inaccurate, and, in most instances, it is acceptable for the analyst to rely on other contemporaneous documents to correct these incorrect dates to ensure the analysis provides a reliable and supportable result.  However, the analyst should fight the urge to modify the logic of the schedules or the durations of activities and make changes that were not incorporated into the schedules contemporaneously.  The insertion of these after-the-fact revisions during the analysis will call into question the reliability and objectivity of the technique and the analyst.  As stated earlier, because the OCPA technique is self-correcting, it will account for missing work activities or missing logic relationships during the analysis and does not require the analyst to apply corrections.
 
Step Two

The second step requires the analyst to identify the changes that were made when the schedule was updated.  In many instances, the need to change the schedule results when the construction plan has to be changed to compensate for unforeseen conditions, added work, or other occurrences that have to be dealt with as the project is constructed.

The schedule can be changed in a number of different ways and the following list includes some examples of these modifications:
•    Added and deleted activities;
•    Added and deleted logic relationships between schedule activities;
•    Changed original durations (if the activity has not started);
•    Increased remaining durations (if the activity has started);
•    Added and deleted constraints;
•    Calendar modifications; or
•    Changing of scheduling parameters (e.g., progress override versus retained logic).

When attempting to identify the schedule changes that were made at the time of the update, the analyst must compare the critical paths of the fully-progressed first schedule and the second schedule.  Because both schedules should have the same as-built information and data date, the analyst should be able to identify any changes made in the latter schedule that resulted in critical project delays or savings.  

It is necessary to separate the delay or savings caused by schedule changes from those resulting from progress, because the delay or savings resulting from the changes will need to be assigned to the appropriate party.

Review/Validation of Analysis

When contemporaneous project schedules are available, the OCPA technique is an objective and reliable method to identify and measure critical project delays.  Reliance on the contemporaneous project schedules and the contemporaneous project documents gives this analytical technique great credibility and deflects complaints that the analysis has been biased to favor a particular position.  Consequently, when the raw materials are available, the OCPA is the preferred technique for analyzing project delays.