Forensic Schedule Analysis and Discretionary Logic

TECHNICAL ARTICLE Forensic Schedule Analysis and Discretionary Logic John C. Livengood Esq., CCP CFCC PSP FAACE Abstract: Forensic Schedule Analysis (FSA) and real time schedule reviews do not handle CPM schedules with significant amounts of discretionary logic very well. In the last decade, major theoretical and practical advancements have been made of which FSA methodology is most appropriate to evaluate schedule delay, largely through the introduction of AACE International s Recommended Practice 29R-03, Forensic Schedule Analysis. Nevertheless, discretionary logic, the type of logic that is not dictated by either the contract or the construction necessity of the project, continues to cause difficulty in creating fair and accurate analyses of schedules during the course of the project. Further, these analytical problems persist in the methodologies associated with post-construction FSA. This article considers several applications and refinements of existing forensic delay methodologies, particularly As-Planned vs. As-Built, which can assist in identifying the as-built critical path and delay responsibility in projects with significant amounts of discretionary logic. T he underlying premise of all Forensics Schedule Analysis (FSA) methodologies is the comparison between what was planned and what actually happened, and from that analysis an explanation of the causation for the difference. As a result of the delay and causation analysis, damages can be calculated. This underlying concept works well in most situations because most construction projects have relatively limited sequences or methods that could be used in construction. For example, in a typical building, the excavation must precede the foundation, and the erection of the steel frame must precede the installation of exterior cladding. In such projects, the required sequence of material installation is driven by the project itself and the laws of physics. However, CPM practitioners recognize that the different groups of logic relationships: contractual, mandatory, and discretionary logic, interact with the forensic analysis methods in different ways. One of these logic groups (discretionary) creates special analytical issues within the context of forensic schedule analysis. Four Major FSA Methodology Families AACE identifies nine methodologies [1] though arguments have been made for more types [2], as well as fewer [3]. This article refers to four major types of forensic schedule delay methodologies. All known schedule delay methodologies fit into these broad groupings. Because every project is different and each have different, even if just slightly different, analysis needs and underlying facts, it could be argued that every forensic schedule analysis performed is a different methodology. Since each separate analysis can, at the most granular level of detail, be distinguished from any other methodology, many analysts have insisted that their particular methodology used is different or distinguishable from other methodologies. Often, these schedule analysts assert their methodology is the best or most accurate method available [16]. Despite these nuances, there are many common characteristics that assist in identifying the four core methodological families [4]. Within each of the four major methodology groups, there are several if not dozens of variations that can be performed that might be considered separate methodologies, but in fact, have much in common. In the sections below, these major families of methodologies will be discussed and the various sub-methodologies will be identified and discussed only as relevant. As-Planned vs. As-Built [1] This methodology compares an initial planned schedule with the COST ENGINEERING MARCH/APRIL 2016 31

as-built schedule or as-built data. This methodology can be performed in great detail or at a very summary level. It also can be performed with relatively little construction phase data. If adequate data is available, it can be a very effective and accurate portrayal of delay events on a project. It is often the fall-back methodology used by schedule analysts when other methodologies are inappropriate, or as a quality check to make more understandable one of the more complicated forensic schedule methodologies. It requires no active computer calculation and relies on the schedule s original logic. However, if based on CPM schedules, the logic of the baseline and the accuracy of the as-built must be verified. The As-Planned vs. As-Built (APAB) is the oldest of the schedule delay methodologies, predating CPM by decades [5]. It compares the original schedule with the actual completed performance and measures delays to activities between the two. This is one of the more easily understood methodologies and one of the more common. It is suitable for projects that lack detailed schedule data and it can be performed at a detailed or summary level. The methodology can be broken into time slices, but such a division may not improve its accuracy. In its most elaborate and detailed application, it can evaluate delays on a daily basis using contemporaneous records and assist in allocating responsibility for each day of delay. Its most significant drawback is that it generally does not allow for the analyst to take into account what the parties were considering during the course of the project, and thereby includes no consideration of the contemporaneous understanding of delay [6]. The As-Planned vs. As-Built methodology remains quite common despite the existence of other methodologies that are less dependent on expert interpretation. This is because the method is easily understandable and can be performed with relatively little data. Its accuracy improves as more information on actual events is included. It also remains common because it can be performed even when some of the underlying data, particularly accurate schedule updates, is unavailable. Contemporaneous Period Analysis [1] This methodology relies on schedules prepared during the course of the project. It is often known as windows analysis. The Contemporary Period Analysis (CPA) method generally identifies delays within specific time periods or windows of time [7]. This comparison is accomplished by comparing the schedule at the start of a time period with its status at the end of the time period. The methodology uses the project schedule updates to quantify the loss or gain of time along a logic path that was or became critical, and identifies the activities responsible for the critical delay or gain. This method relies on the forward-looking calculations made at the time the updates were prepared. Further, it does not involve the insertion or deletion of delays, but instead analyses the behavior of the network from update to update and measures schedule variances based on schedule logic, prepared contemporaneously with the project execution. This is in opposition to the schedule developed at the project outset, as with the As-Planned vs. As- Built methodology or reconstructed after-the-fact logic as used in Time Impact Analysis (TIA) and Collapsed As-Built (CAB) methodologies. As with the As- Planned vs. As-Built, the accuracy of the original baseline is essential. By comparing the status of the project at the beginning of the time period with the project status at the end of the time period, a period-by-period calculation of delays and impacts can be generated. Since the method uses schedules developed during the project, it is often perceived as being the best representation of how the project constructors understood the scope and timing of the work and how they planned to perform future work. Analysis using this method is often assisted by the native format schedules, but the method itself does not require changes to the schedule or other network manipulation. This methodology is generally considered one of the most reliable since the analysis is performed on CPM schedules that were developed, used, and modified during the life of the project. At the same time, if the schedule updates were not maintained on a regular basis and are inaccurate or non-existent, they cannot form a basis for a forensic schedule analysis. The accuracy of these schedule updates is often the first question the analyst must determine when deciding if this FSA methodology is the correct one for the assignment. The second, and often equally important, decision for the analyst is to determine the time-periods for use in the analysis. By combining time windows, the analyst reduces the amount of work and potentially the cost of the analysis, but at the price of less detail. Further, combining time periods can create concurrency or hide important events, including delays and subsequent accelerations. Nevertheless, this methodology, regardless of the 32 COST ENGINEERING MARCH/APRIL 2016

name used, is one of the most accurate of all the forensic delay methodologies available. Time Impact Analysis [1] Time Impact Analyses (TIA) are important and an incredibly useful tool for schedule analysis. Contractors would be hardpressed to identify and quantify potential schedule impacts without the prospective TIA methodology, the methodology for which the TIA was originally developed [8]. Similarly, the Retrospective TIA is widely used and is recognized by courts and commentators because of its rigorous methodology and its close relationship to the chronological sequence of events on the project [9]. Further, it has also been said that a forensic TIA is better able to identify the quantum of an alleged acceleration claim by comparing the actual performance with what would have happened without the acceleration. The accuracy of the original baseline, as well as the contemporaneous updates is essential. Like the Contemporary Period Analysis, this methodology cannot be adequately performed if the underlying data is defective. This methodology requires active use of CPM software. Schedules developed during the course of the project are modified through the addition of new or expanded activities as part of the analysis to reflect delays and impacts, and the resulting changes in the schedule are observed. A TIA methodology compares two CPM schedules with similar data: one reflecting the schedule at the start of an analysis period (such as the beginning of a month or immediately prior to an impact), and the other with an identical CPM schedule, EXCEPT for the inclusion of one or more fragnets, which reflect an actual or anticipated event not previously included in the CPM schedule. The fragnets, developed by the expert to reflect changed events on the project, add or subtract the events through inclusion (or deletion) of activities, revision of logic, and changes in activity. The comparison of the predicted completion dates of these two schedules (before and after the fragnet insertion) determines the quantum of delay reflected by the fragnet. However, Retrospective TIAs have the following problems and should therefore be carefully considered and reviewed: (1) TIAs may appear to be scientific and computer driven; however, they are subject to the similar vagaries of expert opinion as any other methodology; (2) TIAs seemingly scientific method may obscure the analyst s manipulation of the critical path through the development and use of a fragnet or fragnets; (3) TIAs require a detailed and fully functional baseline schedule and set of updates to work properly, which is a requirement that is often impossible; (4) Modifications to the baseline schedule and updates that are needed to permit TIA analysis can be so significant as to make the underlying schedules irrelevant to the plans of the contractor; and (5) The critical path generated is always a projection and may not accurately reflect the actual events on the project [10]. Since this methodology projects future events, some of perceived inaccuracy can simply reflect that the future events and impacts have not yet been realized. Collapsed As-Built [1] The Collapsed As-Built (CAB) methodology is one of the conceptually easiest to understand and hardest to implement in a reasonable and functional manner. Further, the CAB can isolate and segregate owner and/or contractor-caused delays if there is sufficient detail in the as-built schedule. The concept of deleting delay activities to show the impact is easy to understand and present, but difficult to support factually in a legal setting [17]. Because of its reliance on an accurate detailed as-built, it is closely tied to the history of actual events on the project. Finally, it is the only methodology that can be implemented without any baseline schedule or contemporaneous schedule updates. The CAB, also known as the butfor analysis, takes the project as it was actually built and subtracts impacts to show what would have happened if those impacts had not occurred. The collapsed asbuilt methodology has three basic steps. First, the expert takes the as-built schedule of a completed project and identifies the likely logical relationships between the activities and events, based on either the CPM schedules developed for the project or based on the expert s experience and knowledge. Second, the expert removes those delay or impact activities from the CPM schedule. Third, the expert recalculates the CPM schedule, to show what would have happened, but-for the delay/impact events. This methodology is sometimes criticized because the analyst creates the schedule logic as part the analysis. While such creation might be based on contemporaneous CPM schedules, the methodology is often used when no CPM schedules existed during the course of the project. Therefore, a CPM schedule is created based on the actual events, and at best, the expert s knowledge or at worst, guesswork. COST ENGINEERING MARCH/APRIL 2016 33

Three Logic Groups CPM schedules typically have three basic types of logic that the schedule creator can use in sequencing activities as the CPM is developed. They are: Contractual Logic This logic is derived from the contract itself and is usually identified by the owner. It may mandate one section of the building being completed first or some other milestone being accomplished prior to other work being undertaken. For example, a school project may mandate that the classrooms be opened by the start of school in September, but allow the gymnasium facilities to lag until the start of winter. Such logic relationships are necessitated by the operational needs of the owner. This is sometimes considered a type of mandatory or hard logic. AACE defines this type of logic as: Clearly understood work scope allows one to define work activities and logic with precision. The opposite of soft logic [11]. But, this definition fails to distinguish between logic that is required by the laws of man (contract) or the laws of physics. So, an alternate definition of this type of logic is: Logic required by the contract and/or scope of work that mandates certain of the owner s sequence and timing requirements. This logic may be related to the physics of the construction. For example, a date is specified for when the steel must be topped out on a high rise, but may be more associated with some external objective, such as wanting to be the first building on the block over ten stories. Mandatory Logic (also known as Hard Logic ) This logic relationship is common on projects. This is the logic that requires the excavation to precede the footings, followed by the foundation, followed by the structure, and so on. While it is occasionally possible to cheat the requirements of physics (construction the building from the top down), most construction schedules are developed around the contractual and mandatory logic requirements. AACE offers the following definition for this type of relationship: [A] dependency inherent in the nature of the work being done, such as a physical limitation. Used in hard logic [11]. AACE also offers definitions of Irrefutable Logic: Network logic that is rational and compelling and cannot be disputed on the basis of reason, [6] that capture most of the meaning of this logic relationship. So, a more comprehensive definition of this type of logic is: Logic required by the physical necessity of the materials and design. This definition separates the contractual mandates discussed previously and makes the logic connection driven solely by the constraints of the construction [18]. Discretionary Logic (also known as Preferential or Soft Logic) This logic is the primary focus of this article. It is the logic that is developed when, for the particular job in question, there is no contractual or physical necessity to perform the work in a certain order. At the same time, discretionary logic recognizes that there are often valid reasons for performing the work in a certain order. For example, if the contractor is erecting the partitions and sheetrock on the fifth floor of a building under construction, there is probably no contractual or mandatory logic for erecting it from south to north rather than north to south. But there may be good reasons to perform the work in a particular way. For example, if the material lift is on the north side of the building, then a contractor s decision to build the partitions and sheetrock from the south (so he doesn t have to carry the materials past already constructed partitions) makes logical sense. Yet, he could perform the work starting at the material lift and working away from it. The disadvantage is probably a minor loss of productivity since the workers have to exercise special care moving the materials past already erected work. AACE has several definitions of this type of logic. Desirable logic: Network logic that is desirable for the contractor (but not necessarily for the client), based on some preference or advantage. Desirable logic may impose unnecessary conditions that preclude an optimum solution [11]. This is pretty close to the type of logic at issue here, but is reversed. Usually the preference will be to gain some advantage, even if there is another way to perform the work. AACE also proposes for a discretionary logic connection two variations: Dependency defined by preference, rather than necessity. These are typically employed in preferential or soft logic [11]. Preferential Logic: contractor's approach to sequencing work over and above those sequences indicated in or required by contract documents. Examples include equipment restraints, crew movements, form reuse, special logic (lead/lag) restraints, etc., factored into the progress schedule instead of disclosing the associated float times [11]. These three groupings of logic appear in virtually all schedules, but usually have little impact on forensic delay analysis, because most out-ofsequence work does not impact the critical path because of the impact of float. Recall that forensic analysis looks at, late dates, while real projects try to work off of early dates. Nevertheless, each of the delay methodologies is impacted by the degree of discretionary logic. Out-of-Sequence Work Out-of-sequence work can occur regardless of the logic group involved with the activity. For example, the contractor may install the footings and foundations and then come back and 34 COST ENGINEERING MARCH/APRIL 2016

excavate for utility access afterwards, despite the mandatory logic of installing the underground utilities prior to the foundation or footings. Also, the contract may require that the permanent power be installed prior to the emergency generator installation, but the contractor may decide that because of delays to the permanent power caused by the utility, it is essential to have the generators operational much earlier, so as to support the construction. Such out-ofsequence work does occur, but frequently has little impact on the critical path because of either float issues, or the de minimis nature of the out-of-sequence events. The most common type of out-of-sequence work occurs in the following three situations. First, the CPM schedule depicts a mandatory logic relationship, typically a finish-to-start, but the schedule s CPM logic does not fully reflect the true nature of the sequence of work. This usually occurs when the successor activity subject to a mandatory logic connection starts before the predecessor finishes. This is quite common. For example, the CPM calls for completion of partition erection and gypsum board finishing prior to the start of painting. This is logical because you cannot paint until the gypsum board is sanded smooth. Yet, painting often starts prior to gypsum board completion because the painting can occur in an area of work that is complete, even if there are incomplete areas of the gypsum board finishing elsewhere. This is a typical characteristic reflecting a scheduler s short-cut in the logic sequence. However, correcting such short-cuts may make a CPM schedule substantially larger and more cumbersome, hence less likely to be of use in managing the project. Further, construction professionals all understand this type CPM logic shorthand. Forensically, this type of occurrence is seldom of any importance. Such early starts are recognized forensically as a potential shift in the critical path. Regardless of the methodology used, these types of out-of-sequence events typically have no effect on the accuracy of the forensic analysis. The second type of out-ofsequence works occurs when early delays make a work-around of an otherwise mandatory logic tie essential. The earlier example of the out-of-sequence installation of temporary power prior to the availability of permanent power is also an example of a typical construction situation. In this case, delays caused by the utility in providing permanent power make a potential delay to commissioning and testing likely. The contractor s decision to install emergency generators early not only allows the commissioning and testing to proceed (at least for some limited extent), but can also assist in timelier project completion. Forensically, this type of out-of sequence work is important as there likely will be delays to commissioning and testing completion regardless of the out-ofsequence work because final testing contractually needs permanent power. All forensic methodologies are well equipped to recognize and account for such out-of sequence installation. The third and most complicated type of out-of-sequence work is where items that were largely repetitive and have no need for immediate construction successors, are installed in a sequence other than as planned. While this can occur on many types of projects, the most common occurrence is linear projects, such as roads or pipelines. For example, suppose the contractor is building a bridge that has bents, each of which includes multiple piles and pile caps. The project cannot be completed until all the bents are complete and the successor precast beams and concrete deck between the bents is installed. But the order the bents are completed in is irrelevant. There are no mandatory logic restraints as between the bents, but within the bents the sequence must be: piles, pile caps, precast beams, and precast decking. Deck finishing can only be performed after all the bents are completed. Forensically, out-of sequence installation of the bents can create significant analytical problems for some forensic delay methodologies. It is this third out-of-sequence scenario that will be discussed going forward in this article to demonstrate how each of the four major methodologies copes with this discretionary logic. Role of Contemporaneous Updates Since out-of-sequence work is a common occurrence in projects, best practices associated with active project scheduling has recommendations about how it should be considered. Two approaches predominate [12]. The preferred approach is that as out-of sequence work occurs on a project, the next month s update should reflect new logic dictated by this difference from the planned. Generally, this approach works well for adjusting out-of-sequence work and is associated with minor issues of starting the successor early. Primavera P6 calculation setting retained logic is the usual setting for this situation. This policy is more problematic in the cases where there is significant discretionary logic and the actual sequence is substantially different than that planned. Such out-ofsequence work could result in monthto-month schedules not just evolving, but becoming a continual rebaselining that involves significant remodeling of the schedule s logic. The alternate position, which is less widely advocated, holds that the original baseline schedule should not be continually adjusted and that the Primavera P6 setting of progress override should only be used in situations of out-of-sequence work. Again, this position will have relatively little impact on most forensic analysis when out-of-sequence work is associated with minor issues of starting the successor early. This policy creates calculation irregularities when there is wholesale disregard for the planned logic [19]. COST ENGINEERING MARCH/APRIL 2016 35

Choosing the Right Methodology As a general rule, the 11 different items that should be considered in choosing the right delay methodology, as published by AACE, remain in place. These items are described in detail in section five of AACE s RP29R-03, and will in most cases serve the analyst well. They are: 1. Contractual Requirements 2. Purpose of Analysis 3. Source Data Availability and Reliability 4. Size of the Dispute 5. Complexity of the Dispute 6. Budget for Forensic Schedule Analysis 7. Time Allowed for Forensic Schedule Analysis 8. Expertise of the Forensic Schedule Analyst and Resources Available 9. Forum for Resolution and Audience 10. Legal or Procedural Requirements 11. Custom and Usage of Methods on the Project or the Case Nevertheless, as described in the paragraphs below, when significant discretionary logic is involved, there is another overlay of technical capability that needs to be considered [15]. Methodologies and Out-of-Sequence Work The discussion of the four major methodological groups does not follow the typical sequence as presented earlier in this article and in AACE s RP29R-03. In the paragraphs below, the sequence is determined by the least impacted out-of-sequence first and the most impacted last. Collapsed As-Built Out-of-sequence work has no impact on the analysis using this methodology. Because this methodology relies on an after-thefact backward review of the actual project activities and compares that actual sequence to a sequence excluding perceived delays, the change in sequence of activities during the course of the project has no special impact on the results. If out-ofsequence work affects the production rate of the work, then such a change in production would appear as potential delays that could be excluded as part of the analysis. Time Impact Analysis Out-of-sequence work has minimal impact on this methodology since it relies on inserting fragnet changes related to potential delay into the schedule and recalculating. Note that out-of-sequence performance will manifest itself as part of the as-built condition and thus should not impact the delay portion. However, if the claimed delay is the result of out-ofsequence work, then discretionary logic will have a role in the TIA. Generally, the work sequence will in essence self-correct during the course of an analysis. Contemporaneous Period Analysis Out-of-sequence work has only minimal impact on this methodology. CPA relies on comparing the preimpact schedule with the post-impact schedule, so out-of-sequence work will be absorbed into the as-built nature of the second schedule. Again, as with the TIA, if the out-of-sequence work is itself the claimed impact, then it could evidence itself in the analysis. Figure 1 Traditional APAB/DDM 36 COST ENGINEERING MARCH/APRIL 2016

It is important to realize that both the TIA and the CPA rely on schedules that are updated. Therefore, it is essential that out-of sequence work, when it occurs, be integrated into revised logic in the next update. As with a TIA, the work sequence will in essence selfcorrect during the course of an analysis. As-Planned As-Built The biggest impact on FSA results, if there is substantial discretionary logic and resultant out-of-sequence work, is associated with the As- Planned vs. As-Built (APAB) methodology. Because the starting point of this methodology is the asplanned schedule, significant logic variations from that plan create correspondingly significant potentialities for delay and errors in forensically calculating its impact. It is, of course, recognized that this is one of the principle reasons that many FSA experts believe that the APAB methodology is a poor choice for delay analysis [5]. It is axiomatic that the larger the project, the more complicated the project, and the longer the project is in production, the less likely the ABAB will result in reasonable or accurate analysis results [1]. Nevertheless, APAB remains one of the most commonly used FSA methods [13]. Further, it can be argued that in cases with massive discretionary logic and associated outof-sequence work, methodologies like TIA and CPA, which relay on accurate contemporaneous updates, are not appropriate to perform delay analysis. Using a Daily Delay Measure to Assist [14] The Daily Delay Measure (DDM) is an enhanced procedure within the APAB methodology identified in RP29R-03 [1]. It compares the planned late start and finish dates progress with the actual start and finish dates on a periodic basis. Generally, this analysis technique uses a mathematical formula to compare the amount of actual time expended against the planned amount of time expended. For example, assume the planned activity was 10 calendar days long and its late planned start date was 01-April, and the actual start date was 01-May. On that date, the activity would show it delayed 30 calendar days. Upon its completion on 20-May, the DDM would show the activity 40 calendar days late. Since the activity lost a half day for every day of progress (10/20), the activity would have been 35 calendar days late on 10- May. By making this calculation for every day for every activity, a detailed picture of the project s delay can be assembled. The analysis can be done at any frequency identified by the analyst: daily, weekly, and monthly are all useful depending on the level of detail required. The DDM calculates the status of individual activities by positive and negative numbers indicating days of delay. By doing this for each activity and comparing them side by side, it provides a detailed look at potential critical path activities, because the analyst can tell at a glance which activities are the most delayed compared to their late dates. This technique automatically accounts for float differences by using the late dates. It does not identify the as-built critical path [14]. While the comparison can be made between the early and actual dates when the late dates are unreliable, it is better to compare late dates with actual dates [20]. Any delay indicated by the comparison using late dates is a true delay rather than consumption of float. As a result of that exercise, any float associated with the duration of a schedule activity is excluded. Activities that have float (and accordingly are not on the asplanned critical path) will generally not appear to have been delayed during the early stages of analysis since they will appear to be ahead of schedule because of their float. As the analysis progresses through a project s performance however, the activities that initially had float, if they were delayed for duration in excess of the value of that float, can become critical, thus overtaking one or more of those activities originally on the project s asplanned critical path. Traditional Daily Delay Measure Traditional APAB/DDM procedures will not provide an accurate evaluation of delays when there is substantialout-of-sequence work. This is evident in that comparing an event that was supposed to be performed first with its actual timing could show great variation from activities that were significantly ahead of schedule to those that were significantly behind schedule. Such an outcome would not provide the analyst with an accurate picture of the overall delay trend of the project. Figure 1 shows this unrealistic result of the Traditional DDM by plotting the cumulative delay in the vertical axis and the date of that delay on the horizontal axis, using the DDM procedure. For comparison, the Adjusted Traditional DDM is shown that simply reflects normalization of the excessive variation. Not surprisingly, this shows that there is wild variation in the cumulative delay as out-of-sequence activities are compared to the original baseline. Even as the overall trend shows more than 100 calendar days of cumulative delay, this graphic representation shows that the work may be ahead of schedule. Production Based Daily Delay Measure There are at least two variations of the APAB/DDM technique that address this problem. Both were first identified and used in an entirely different context when first described in 2003 [14]. The DDM methodology, described in AACE International s RP29R-03, largely conforms to the traditional technique proposed in 2003. As such, it is a powerful tool for helping to identify candidates for a project s critical path and when that path may shift from one delayed sequence to another. As used in evaluating out-ofsequence performance, it can be adapted to compare the planned rate of installation of similar elements to the actual rate of those same elements. In the example of the COST ENGINEERING MARCH/APRIL 2016 37

Figure 2 Traditional APAB/Production Based DDM installation of repetitive bridge elements (piles, pile caps, and piers), the method compares the date of the first planned element to the actual date of the first planned element, the second actual unit dates to the second planned dates, and so on. This process is repeated for each type of element. It is important that the units are essentially the same. It works well for comparing pier installation or units of distance on a roadway project. Such a comparison therefore eliminates the penalty for out-of-sequence work because it pretends that the planned sequence was the same as the actual sequence, just delayed because of poor production; or other factors such as late design, weather, or delayed approvals. Figure 2 depicts this Production Based DDM in comparison to the Adjusted Traditional DDM. It shows that the overall delay to the project is the same, but the delay is measured incrementally as it actually occurs. This is important if the causes of the delay are being analyzed. It may be that during the production there was some detail change that impacted production rates. If so, the incremental approach would show when it occurred and the time-related impact. Cost Based Daily Delay Measure A cost based APAB/DDM is a second variation of the procedure that can yield accurate results by identifying the amount of delay incrementally when it actually occurred. This technique requires the schedule to be cost loaded. If not already cost loaded, the analyst could manually cost load the major activities groups and create a reasonable representation of a true cost loaded schedule. Assuming planned schedule is cost loaded, either through original cost loading or an expert approximation, a table can be created that shows the anticipated earnings (not billings, since they will likely reflect withheld retainage). Using that same cost values tied to the actual dates for the appropriate activities, a comparison can be made with the actual earnings. Traditionally, this is shown in an S-curve; however, using the planned and actual dates of the earnings, a schedule delay comparison is possible. This method of course is similar to an earned-value measure. The difference is that it is predicated on time differential from the as-planned to the as-built, so it actually measures delay. It is important to accommodate two potential issues in this cost based DDM analysis. Large equipment purchases or installations can seriously alter the cost model for both the planned and actual dates. In performing this type of analysis, it is recommended that such large material or equipment purchases be eliminated from the calculation. A second adjustment should be made for change orders. The value of the change order needs to be added into the proper place in both the planned schedule and actual schedule. Figure 3 shows this Cost-Based DDM in comparison with Production- Based DDM and the Adjusted Traditional DDM. The similarity of the two cumulative delay curves generated by the alternative DDM techniques can give the analyst confidence that the overall depiction of the delay is accurate. At the same time, the differences warrant a detailed review to ascertain the causes. In Figure 3, the analyst 38 COST ENGINEERING MARCH/APRIL 2016

Figure 3 Cost Based/Traditional/Production DDM identified the principle reason for the divergence between the two lines is related to valuation differenced caused by the length (and therefore cost) of some of the deck/precast elements. Conclusion In choosing a forensic delay methodology, the analyst should follow the 11 criteria identified in AACE Recommended Practice 29R-03, Forensic Schedule Analysis [15]. However, when significant discretionary logic in a schedule has resulted in significant out-of-sequence work, there is an additional overlay of method selection to consider. Of the four basic methodology groupings, which AACE has divided into nine distinct forensic schedule analysis methodologies, three of the four can probably be used without modification. However, each of these methodologies has well known shortcomings, whether it is minimal acceptance in courts of law in the U.S. (Collapsed As-Built), or the need for accurate baseline and schedule update information, which is often unavailable (Contemporary Period Analysis and Time Impact Analysis). The fourth major methodology group, the As-Planned to As-Built methodology, if used in conjunction with the enhancement of the DDM technique, can provide accurate incremental delay data where other methodologies may fail. The APAB/DDM methodology, when used with either a production based adjustment or a cost based adjustment, can provide an accurate identification of when and by how much the project was delayed, thus facilitating identification of the causes of that delay and eventual damage calculations based on that data. REFERENCES 1. K. Hoshino, C. Carson, and J. Livengood, 2011. AACE International Recommended Practice RP 29R-03, Forensic Schedule Analysis, Section 3, AACE International, Morgantown, WV. 29R-03 (2011). 2. S. Dale and R. D Onofrio. Reconciling Concurrency in Schedule Delay and Construction Acceleration. (2010) 39 Public Cont. L.J. 161. 3. B. Bramble and M. Callahan. Construction Delay Claims, (3d ed.), Aspen 2000. 4. P. Kelly and W. Franczek. Fall, 2013, Clearing the Smoke: Forensic Schedule Analysis Method Selection for Construction Attorneys. The Construction Lawyer, p.30. 5. S. Dale and R. D Onofrio. Construction Schedule Delays, West Thompson Reuters, 2014, Pages 598 and 471. 6. P. Kelly and J. Livengood. Forensic Schedule Analysis Methods: Reconciliation of Different Results. Transactions 2014, AACE International, Morgantown, WV. 7. L. Schumacher. Quantifying Delays on Construction Projects. Seattle Daily J. of Commerce, Dec. 24, 1991; and L. Schumacher. Apportioning Delay on Construction Projects. Seattle Daily J. of Commerce, Dec. 25-26, 1991. 8. T. Calvey and R. Winter. AACE International Recommended Practice RP 52R-06, Time Impact Analysis As Applied in Construction, 2006, AACE International, Morgantown, WV. 9. J. Wickwire, T. Driscoll, R. Hurlbut, and R. Hillman. Construction Scheduling: Preparation, Liability COST ENGINEERING MARCH/APRIL 2016 39

and Claims, 3rd edition, 2010, 8.13, Aspen Publishers: P. Bruner and J. O Connor. Bruner & O Connor Construction Law, Vol. 2, Section 15:120-136, West Thompson Reuters, New York. (2007). 10. J. Livengood. Retrospective TIA s Time to Lay Them to Rest AACE International Transactions, 2007. 11. AACE Definitions, AACE International Recommended Practice No 10S-90, Cost Engineering Terminology, AACE International, Morgantown, WV, 2014. 12. GAO Schedule Assessment Guide. (May, 2012) (GAO 12 12OG). 13. N. Braimah. An Investigation into the Use of Construction Delay and Disruption Analysis Methodologies. Doctoral Thesis, University of Wolverhampton, UK, August 2008. Page 140. 14. J. Livengood. Daily Delay Measure A New Technique to Precisely Measure Delay. AACE Transactions, 2003. See also R. Seals. Continuous Delay Measurement and the Role of Daily Delay Values Fully Explained. AACE Transactions, 2004. 15. K. Hoshino, C. Carson, and J. Livengood. 2011, AACE International Recommended Practice RP 29R-03 Forensic Schedule Analysis, Section 5, AACE International, Morgantown, WV. 16. It is instructive that many of the experts who object to The Recommended Practice on Forensic Schedule Analysis (RP29R-03) have their own pet methodologies that were insufficiently distinct from other methodologies to be independently identified they were considered to be a subset of nine that were identified. 17. The difficulty in finding factual support for the collapsed as-built methodology has two root causes. First, the methodology is often used when there is no effective baseline schedule to show how the contractor reasonably planned to perform the work. Second, as discussed in the paper, the expert s development and control of the after-the-fact schedule logic make it subject to criticism of it being only weakly related to the events in the field, and at the extreme, contrived. 18. The issue of logic controlled by resource restraint could be considered as either a mandatory restrain or as a discretionary restraint. Depending on where and when the work is being performed, the lack of equipment and materials may be just as real as gravity in controlling the sequence of construction. For discussion in this paper, it has been considered controlled by discretionary logic. 19. The situation where the contract forbids or sharply curtains logic revisions in updates is not addressed by the discussions in this paper. In such cases, the contractor has a more complicated problem because the owner has drastically reduced the contractor s risk-mitigation options. Since the schedule is developed and maintained by the contractor, provisions that restrict the contractors ability to manage the schedule are ultimately selfdefeating for the owner 20. The reporting of actual finish dates is an issue of significance in forensic schedule analysis. Because activities soften linger for a long time after they are effectively complete, it is important to know if the reporting convention is 100 percent complete or effectively complete, which may be 90 percent or 95 percent. ABOUT THE AUTHOR John C. Livengood Esq., CCP CFCC PSP FAACE, is with Navigant. He can be contacted by sending e-mail to: john.livengood@navigant.com FOR OTHER RESOURCES To view additional resources on this subject, go to: www.aacei.org/resources/vl/ Do an advanced search by author name for an abstract listing of all other technical articles this author has published with AACE. Or, search by any total cost management subject area and retrieve a listing of all available AACE articles on your area of interest. AACE also offers pre-recorded webinars, an Online Learning Center and other educational resources. Check out all of the available AACE resources. 40 COST ENGINEERING MARCH/APRIL 2016