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THE PLANNING FALLACY AND ITS EFFECT ON REALISTIC PROJECT SCHEDULES

FORENSIC SCHEDULE ANALYSIS AND DISCRETIONARY LOGIC TECHNICAL ARTICLE The Planning Fallacy and Its Effect on Realistic Project Schedules Jeffrey Valdahl and Shannon A. Katt

performing similar tasks. Kahneman Abstract: “How long do you think that task will take?” It’s a question that is states that the planning fallacy asked frequently during the course of a project, but is often answered with describes plans and forecasts that: little or no factual basis. Project team members typically underestimate the time needed to complete a task they are responsible for. This tendency has been referred to as the “planning fallacy,” and it can have a dramatic effect • Are unrealistically close to best- on developing a realistic overall project schedule. This article examines var- case scenarios ious causes of the planning fallacy, including , lack of task un- • Could be improved by consulting packing, and short memory. the statistics of similar cases [7]. As a project manager or planner, it is important to recognize when these psychological effects are impacting your project schedule. This article uses Kahneman also describes the examples from various projects to show where this challenging planning exercise that first led him to describe issue is likely to occur. Identifying where adjustments need to be made, at the concept. He was working with a both the task and overall project level, is essential in developing a project team of colleagues to write an schedule that is both achievable and reasonable. ★ academic textbook. After progressing for about a year, he asked each team ow long do you more on psychological research than member to independently write down think that task will on traditional project management how long they thought it would take to take?” Anyone who issues. As an experienced project finish a draft of the book. The “H has participated in a manager or planner, it is important to estimates generally centered around planning discussion to lay out a proj- recognize when this effect is occurring two more years, with a range of one ect’s schedule will recognize this fun- and make adjustments during the and a half to two and a half years. damental question asked to project development of the schedule. This He then asked one colleague who team members. It often initiates an un- article explores common reasons for had extensive experience with other settling pause while the person respon- the planning fallacy, provides insight academic textbooks how much longer sible for the task contemplates the on typical situations where it occurs, it had taken similar teams to finish a “correct” answer. Frequently, the an- and offers techniques to help develop draft, once they had reached the same swer is a gross underestimation of the more realistic project schedules. point in development. The actual duration needed to complete experienced colleague gave this the task. When these individual, short- The Planning Fallacy Defined question additional thought and ened task durations are linked to form The planning fallacy concept was delivered some bad news: it typically the full project schedule, the result is first used by and took about seven more years to finish. often a misrepresentation of the time to describe the Even worse — about 40 percent of the needed to complete the overall project. tendency to underestimate the time other teams never finished their books This tendency to underestimate needed to complete a given task. at all. task durations is commonly referred to More importantly, they found that this Kahneman’s textbook team was as the planning fallacy [2]. Theories on underestimation happens even when shocked to hear the actual timeframes why this effect occurs tend to focus people have previous experience in of similar projects. The team could not

COST ENGINEERING MARCH/APRIL 2016 21 imagine what might take them that The Project • YYZ Project Manager: long, so they promptly noted the Planning Environment “Yeah, but those were caused by comparables but stuck with their When project schedules are our equipment vendors, not us. original duration estimate. Kahneman developed in a group environment, We will just source our equipment states that his team had committed a gathering project team members in a from another vendor” planning fallacy by relying on internal conference room to walk through estimates that, “were closer to a best- their assigned tasks in the context of This is an example of group case scenario than to a realistic the entire project is a common optimism bias. Both individuals and assessment.” The textbook ended up approach. Various tools are used to groups often attribute past successes taking eight more years to complete! plan the project, from sticky notes to to themselves but failures to outside Research on the planning fallacy specialized software that facilitates a factors [14]. Typical thinking is that has been conducted primarily in the group collaboration effort. A project problems that happened last time area of , rather than in plan and schedule that the full project were one-offs and will not happen project management. The various team “buys into” are the measure of again. There is always a chance that research areas include the effects of success. the new project will have valid lessons deadlines, perceived durations of Unfortunately, research suggests learned from previous efforts, but similar previous tasks, level of that this group planning environment complications that happened before planning detail, anchored dates, often exacerbates planning fallacy must be recognized [8]. individual versus group planning, issues. Group predictions tend to be Projects planned backward from egos, team power structure, and bias. more optimistic than those set by an a desired end date can exhibit this From that research, some methods individual. Researchers have group bias. Activities frequently get have been developed that try and described this group accentuation shoe-horned into desired time frames offset potential effects of the planning effect as a result of dynamics between and have unrealistically short fallacy. team members during the planning durations. Even though schedules are process. Even though individual most often easier to develop “when Recognizing the Planning Fallacy members can act as observers to you know the answer first,” project A savvy project manager or other members’ tasks, any teams should be cautious when planner will recognize when their impartiality tends to be planning activities to meet interim project team is becoming aggressive overshadowed by being an active date benchmarks. Projects frequently in their activity duration estimates. participant and stakeholder to the have hard completion dates (e.g., the Often, recognition happens when entire group’s optimism [3]. Olympics), but their activities are activity sequences or project phases To examine various group always executed in the forward appear to be forced into time frames planning scenarios that lead to the direction from the start, regardless of established by top-down planning planning fallacy and overly optimistic how they were planned. Unrealistic, techniques. In other cases, an project schedules, we will visit a backward-planned durations can lead unrealistic project schedule is the planning meeting for the fictitious YYZ later on to sacrifices in scope, cost, or output of a collaborative planning Plant Expansion Project. quality to meet deadlines that may session driven by a few influential have been established without a solid team members. These situations need Project Team Optimism Bias basis. to be recognized during the planning The project environment also process and then offset with • YYZ Project Director: tends to produce an inherent bias by challenges to the basis of optimistic “Two years is more than enough team members. There is a strong durations. Frequently, the person time to design and construct the desire to keep the project moving questioning the validity of the expansion project.” forward at all times, with required planned schedule is not very popular • Construction Manager: approvals and funding. This bias can with the rest of the group [1]. “Absolutely. If you get me the lead to overly aggressive schedules for The following sections describe design and major deliveries by the the next phase of the project in order project schedule planning situations beginning of the year, we will to comply with economic and that often promote planning fallacy have it up and running by the operational targets established effects. Identifying when these occur holidays.” outside of the project [2]. No one who is a key to offsetting them and to • YYZ Operations Manager: works in the projects business enjoys developing a more realistic overall “Remember we ran into some the uncertain period between project schedule. problems when the previous unit assignments, especially after a project was started up. gets cancelled. Terminating a project before it is completed is often a correct decision, but schedule bias

22 COST ENGINEERING MARCH/APRIL 2016 from those directly involved in the Schedule Anchors modeling department eight project can cloud an impartial project weeks to complete the model evaluation. • YYZ Engineering Manager: before we can have a review” “So our current engineering • YYZ Project Director: Team Member Egos schedule shows that all detailed “Eight weeks???” drawings will be issued by the end • YYZ Team Member: • YYZ Project Director: of April.” “Yes. This is a pretty complex “Some of the higher-ups are • YYZ Project Sponsor: model, especially for the new saying there is no way the plant “Wait. In the approved funding expansion pipe routing. It will expansion construction can be document we said that we would take a solid eight weeks to resolve done in a year.” have engineering done four clashes and finalize the model.” • YYZ Construction Manager: months earlier in December.” • YYZ Project Director: “We will make it happen. I have • YYZ Project Manager: “Well, we do not have eight never missed a deadline on one of “Yeah, but we added more weeks. Let us put four in the my projects and I am not going to equipment scope and are still schedule. Are you OK with that?” start now.” waiting on vendor drawings, so • YYZ Team Member: • YYZ Project Manager: that is adding time to “Um, I guess so.” “I just want to make sure we do engineering.” • YYZ Project Director: not promise to meet the end of • YYZ Project Director: “Good, four weeks it is.” the year deadline and then not “Well, we originally told the deliver.” Board the end of December for Power and intimidation can • YYZ Construction Manager: engineering completion. Unless become a major factor in group “Look, I am not going to have you two want to stand in front of schedule planning sessions. If a somebody from the corporate them and explain why we cannot participant has legitimate power over office telling me how long it will make it, we need to make it subordinates on the project team, take to get my construction happen.” that high-ranking individual can done.” dominate activity duration Specific dates tend to establish discussions. Studies show that groups Nobody likes to have their ability themselves in project stakeholders’ containing a powerful member to perform on a project questioned, minds. Research in this area suggests consistently led to more optimistic especially by someone outside of the that when quantities and overall and less accurate time predictions project. Protecting egos and self- scope of a project are still not [15]. This power influence leads to a esteem is a common occurrence in established, people are still relatively selective focus on a dominant, goal- business and in a high-pressure comfortable in estimating a project’s focused opinion with less focus on project environment [14]. “If completion date [10]. These initial often-relevant, secondary information. everyone else would just get us what estimates, even though often without An effective planning facilitator we need and then stay out of our way, a firm basis, are often “anchored” to will recognize when this situation is we could get our tasks done when we the project and to its stakeholders occurring and try to coax additional say they are going to be done.” Any going forward. opinions from other intimidated team delays that occur are often blamed on Even when new information, or members; this can be quite a someone else, or on factors outside of additional scope, suggests that the challenge in a group environment. a team member’s control. completion date should be extended, Sometimes a “divide-and-conquer” Unfortunately, this individual stakeholders often are anchored to approach is effective where smaller, optimism brought on by team the original date and are reluctant to similar-level groups are assembled to member egos can lead to a very change [8]. If the original anchored obtain schedule information from aggressive schedule when all tasks are date is based on a biased prediction, multiple sources, which is then combined. All of the optimistic team any adjustments made to reflect integrated later. members must deliver on ego-driven specific project information will promises for the project schedule to usually still result in an unreasonable Short Memory stay on track. When the inevitable revised date [12]. delay occurs, the unrealistic project • YYZ Construction Manager: schedule is exposed, and frequently, Power Bias “We have three months in our finger-pointing begins. schedule to construct the • YYZ Team Member: foundations for the new “After we receive all the vendor expansion equipment.” information, it will take our

COST ENGINEERING MARCH/APRIL 2016 23 • YYZ Project Planner: information. A collection of “I came up with a timeline for the “Three months seems pretty completed, “as-built” project eight separate reviews and short. When we did the schedule information should be a approvals we need to get. With foundations for the previous priority for project organizations. As- the holidays falling right in the expansion project during the built activity records could evolve into middle, it looks like it is going to winter months, it took a pretty a statistical distribution of actual take at least four months from long time. ” durations from which various activity start to finish ― and that is if all • YYZ Construction Manager: durations that best correlate to the the external reviewers are “I remember, but there is no way current project parameters may be available when we need them.” it was much longer than what we selected. Three-point duration • YYZ Project Manager: are showing.” estimates (optimistic/most “That is unbelievable! Looks like I • YYZ Project Manager: likely/pessimistic) could also be need to put in for some advanced “Can you pull up the schedule referenced for schedule risk analysis. funding to keep this project from the last expansion project This approach to mitigating the moving forward.” and look up how long it took?” planning fallacy is a forecasting • YYZ Project Planner: method advocated by Bent Flyvjberg The level of detail in a project’s “Here it is. Wow! It took us about [4]. planned schedule can have an effect five and a half months until we on its overall duration. Research in were done with the foundations.” Task Unpacking this area has focused on the “task • YYZ Construction Manager: unpacking” scenario where longer “That cannot be right, and we will • YYZ Project Manager: activities are broken down into more have better weather this winter. I “Let us put two months in the detailed, shorter-duration tasks. am going to stick with my three planned schedule for reviews and Results show that when this task months.” approvals before full-funding unpacking is incorporated to more approval.” accurately reflect the sequence of How long did the previous project • YYZ Project Planner: steps needed to complete the take to perform the same sequence of “I am not sure the standard two- summary activity, the total estimated tasks? Project managers and even month rule-of-thumb is enough duration is typically increased [6]. team members that performed the anymore.” Interestingly, near-term activities that work prior have a tough time • YYZ Controls Manager: are unpacked normally have their accurately remembering how long it “Do we know all the required durations increased more than took to complete past activities. This stage gate reviews and approvals activities that are further in the “memory bias” has been studied that we need to go through under future. This suggests that people can extensively in conjunction with the new project process?” focus more easily on developing planning fallacy. These incorrect • YYZ Project Director: detailed task sequences when memories of past task durations are a “I know we are supposed to have requirements have been set for major cause of biased future external reviews for both cost and performing upcoming work. predictions [11, 12]. schedule. I think there is going to The average project manager or Vierordt’s Law (1868) says that be an internal project audit too, planner might react to this research short intervals of time tend to be but I am not sure if it has been by requiring extremely detailed overestimated, while long periods of finalized yet.” schedules for projects to obtain a time are typically underestimated. • YYZ Project Manager: more accurate (and often longer) This effect can lead to incorrect “Well, if they really want this overall duration. But development of approximations of the actual project to meet the end of the large, detailed schedules for projects durations on past projects or phases. year deadline, we cannot take also takes extended time and Additional studies show that more than two months to get resources. Finding the level-of-detail providing people with the accurate funding.” “sweet spot” where sufficient actual duration of past tasks improved • YYZ Controls Manager: breakdown exists for the critical path their prediction accuracy of future “Let us try and lay out all the or key sequences, while maintaining similar tasks [13]. However, planning required steps once we find out reasonable development time, can be fallacy effects can still play a role everything we need to do.” difficult. Task unpacking research when historical information is suggests that a better approach could discounted or ignored [8]. Three Weeks Later… be a rolling wave of schedule A key factor in overcoming this development with more detail for memory bias is the availability of • YYZ Project Planner: near-term work and summary-level accurate, past project schedule activities for work in the future.

24 COST ENGINEERING MARCH/APRIL 2016 Figure 1 – Example Schedule Metric (Construction Duration vs. Labor Hours)

Combating the Planning Fallacy The planning fallacy is a real psychological phenomenon that requires a focused effort to offset its effect. Discussed here are a few of the many suggested options for making that happen.

Inside vs. Outside View and High-Level Sanity Check The inside view relates to the perspective of project participants who draw from their own personal knowledge and experience. In contrast, the outside view draws from external sources of information [5]. It has been found that using feedback from other similar projects (outside Figure 2 – Example Schedule with Ordinal Dates view) will lead you to a more realistic against the durations of comparable reality. This is particularly common schedule [13] than the inside view, past projects. when activities are weather-sensitive which tends to be clouded by an and the desire is to perform that work inability to see one’s own Ordinal Dates during the summer months. To shortcomings. Whenever possible, Project team members have a combat this tendency, it is often you should strive to obtain external tendency to fixate on a calendar date, useful to set the calendar strip of the data for similar projects to provide often anchoring to it, as discussed schedule to ordinal number dates as unbiased information. previously. They have predisposed depicted in Figure 2. Figure 1 shows an example of a ideas of when they expect to perform Seeing that concrete work is high-level metric comparison various phases of the project and will planned for month three does not between construction duration and adjust durations to make that happen, enlist the same reaction as concrete labor hours. Similar metrics can be even if those durations conflict with work planned for January. Once the used to validate the current plan

COST ENGINEERING MARCH/APRIL 2016 25 ordinal calendar is converted to durations. The schedule is then obstructions are discovered, weather named calendar periods, some analyzed in a Monte-Carlo type is worse than anticipated, productivity seasonality duration adjustments may simulation using those low/high/most is not as good as estimated; the list of be required for potential weather- likely durations. The result is a set of common risks is endless. In addition, impacted work. probabilistic durations for the overall there are project-specific risks that schedule. A thorough analysis will may be even more impactful. If the The Pre-Mortem attempt to remove inherent biases in team can make an effort to identify Another helpful tool for getting the base schedule and replace them those risks and how they may affect project participants to accept that with more realistic, optimistic, and the schedule, its members will unplanned things do happen is to have pessimistic cases. highlight those risks that need to be a pre-mortem discussion [9]. A pre- The result is often a completion carefully monitored and mitigated. mortem assumes that you are at the date far beyond that of the project The probabilistic analysis results end of a project and you have plan and one that is difficult to accept provide valuable information to the completed late. Looking back, what [1]. In fact, an achievable deterministic project team regarding alternate were the things that were likely to target schedule is rare even in a scenarios that can ultimately drive the have caused the delay? Did you not fraction of analyses simulations. There project’s schedule. Once the range of properly assess risks that impacted are several significant benefits to driving probabilistic critical paths is the schedule, like late equipment performing a risk analysis on the evaluated, the project can reserve delivery, or possibly were you overly project schedule, in addition to the schedule contingency in key locations optimistic in your labor productivity? output of an actual probabilistic in the activity network to reflect Maybe you assumed you would get analysis. possible anticipated slippage in the funding at a particular time and it was First, the analysis itself forces the plan [11]. The resulting “risked delayed. A focused effort to identify team to take a close look at the schedule” becomes a more realistic project risks at the beginning will durations and confirm their validity. In plan when duration uncertainty is facilitate mitigating those risks or many cases, the team realizes that applied to the project. Active avoiding them completely. they have been too optimistic in their management of the risked project planning and will adjust durations to a schedule includes updating the Resource more reasonable length. A third-party analysis periodically as execution Overpromising/Awareness facilitator, however, can get the team changes during the project’s life cycle. Schedules are often developed to focus on the outside view of the This approach can be an effective with no consideration to the resources project, bringing with it wider ranges solution to overcoming the inherent needed to complete the plan. of potential durations for given bias present in early-date, critical path Reviewing the resource requirements activities. method project schedules. against the schedule will enable a Second, the dialogue that takes review of what the labor requirements place as part of the analysis process The Coach’s Challenge will be. Are they reasonable? Or are greatly enhances the team’s Sometimes the most useful thing the durations so optimistic versus the knowledge of the project, schedule, you can do for your project is to bring estimated labor hours that more and potential risks. Bringing as many in an unbiased third party to facilitate workers are required than can project stakeholders as possible a high-level planning session [1]. This physically work in the area? Are there together to discuss all aspects of the is often practiced when performing a peaks in the resource profile that can project tends to force each participant schedule risk analysis. Frequently, be smoothed if a more realistic to look beyond their specific realm of project teams are too close to the (longer) duration is set, particularly for responsibility. The result is that team details and don’t want to accept an activities not on the critical path? members often change the durations alternate view of the project’s of their assigned work. schedule risks. The concept of the “Risked” Schedules “Coach’s Challenge” can be used Linking a pre-mortem with a Another benefit of risk analysis during schedule review sessions. The Coach’s Challenge (see explanation centers on risk identification. Base facilitator or a designee has the later in this article) is the process of plans rarely include delays or impacts authority to throw a “challenge flag” performing a risk analysis on the resulting from risks inherent to the when they see the team making a project schedule. A probabilistic project. Project schedules are often decision that does not make sense schedule risk analysis reviews the developed with the assumption that when looked at from an outside view. durations set by the project team and everything will go as planned, though Like the Coach’s Challenge in the questions them. For each activity this assumption is rarely supported. National Football League, the flag reviewed, the group determines the Equipment fabrications take longer throw identifies a decision that needs optimistic, pessimistic, and most likely than quoted, underground to be more carefully looked at and

26 COST ENGINEERING MARCH/APRIL 2016 then tested for validity. factors that determine a project’s manager or planner will recognize Coach’s Challenges are most cost, and in turn, its completion date. these effects and take steps to frequently issued during the ranging In reality, the collaborative mitigate their impact on the schedule. session of a schedule risk review. planning environment has too many Techniques like ordinal dates, a pre- While working with team members to advantages that offset its potential mortem, the Coach’s Challenge, and determine optimistic and pessimistic limitations. The common risk-adjusted schedules can often be durations, it is not uncommon for the understanding of the project scope, used to offset unrealistically short discussion of an activity to highlight a work breakdown structure, activities, schedule durations. Effective project potential risk or significant variance in and relationships is inherently teams welcome an outside view of the planned duration from that valuable to planning session their plan and use comparative data previously experienced. The participants. Key hand-off points to validate and provide a solid basis consensus may be to extend the during execution of the work must be for their schedule. duration, but the person ultimately accurately represented in the An examination of the planning responsible will disagree for any of the project’s schedule. The person fallacy might suggest that the ultimate various reasons discussed previously. building the schedule network is a solution is to simply extend planned It is at this point that the challenge primary beneficiary of these schedules out so that they reflect an flag is thrown to focus the discussion collaborative planning sessions. overly conservative estimate of the on how the planned duration was However, planning fallacy project’s duration. In the project developed. The discussion may either limitations of this group planning world, however, this approach is verify that the planned duration has a approach suggest that more activity simply not viable. Projects should be solid basis as currently shown, or may duration validation is needed before planned to complete in a sensible lead to a revision. establishing a schedule as the project amount of time, including baseline. External reviews, contingency. Recognizing and Less Collaborative Planning? benchmarking, resource analysis, and overcoming potential planning fallacy The collaborative approach to high-level sanity checks are all issues during development will developing a project’s schedule is valuable techniques to combat produce better project schedules that often in contrast to how the project’s potentially optimistic and inherently are both achievable and reasonable. cost is estimated. Even though the biased project schedules. When scope and associated quantities are combined with the synergistic REFERENCES often reviewed with the full project benefits of collaborative planning, this 1. Birken, Emily Guy, 2014, This Is team, the project’s estimate is two-step approach can produce a Why Your Projects Always Take typically developed independently. schedule that is both accurate and Longer Than You Expect, Estimated hours and cost are backed up with a solid basis for its WiseBread - Living Large on a computed using detailed comparable durations. Small Budget (web site blog), and historical information as a June 16, 2014, verifiable basis. Why are these Summary www.wisebread.com. approaches so different? Why do The planning fallacy is a tangible 2. Buehler, Roger; Dale Griffin, and participants in a group schedule influence that can lead to planned Michael Ross, 1994, Exploring the planning session feel so confident in schedules that are doomed to fail, "Planning Fallacy": Why People proposing activity durations (often even before a project starts. Underestimate Their Task with little or no basis), when they Optimistic and often biased estimates Completion Times, Journal of would be very hesitant to throw out of individual activity durations can Personality and Social an estimate of its cost? combine to produce a schedule that Psychology, Vol. 67, No. 3, Pages Research implies that planning severely underestimates the total 366-381. fallacy effects are greater in a group time needed to complete a project. 3. Buehler, Roger; Deanna setting than when task durations are The planning approach, especially in a Messervey, and Dale Griffin, estimated independently [3]. When group environment, can often 2005, Collaborative Planning and combined with the often fragile exacerbate the inside view taken by a Prediction: Does Group Discussion dynamics that tend to surface during project team when proposing an Affect Optimistic Biases in Time group planning sessions, maybe the overly aggressive schedule. Estimation?, Organizational collaborative planning technique Planning fallacy research shows Behavior and Human Decision should not be the preferred approach. that other factors, such as memory Processes, Pages 47-63. Perhaps project schedules should be bias, power influence, egos, group 4. Flyvjberg, Bent, 2008, Curbing developed more like estimates: with optimism, and level of detail, can play Optimism Bias and Strategic extensive analyses of scope and other a major role during schedule Misrepresentation in Planning: development. An effective project Reference Class Forecasting in

COST ENGINEERING MARCH/APRIL 2016 27 Practice, European Planning Judgments, Journal of ABOUT THE AUTHORS Studies, Vol. 16, No. 1. Experimental Psychology: 5. Gilovich, Thomas; Dale Griffin, Learning, Memory, and and Daniel Kahneman, 2002, Cognition, Vol. 35, No. 1, Pages Chapter 14, Inside the Planning 81-92. Jeffrey Valdahl is Fallacy: The Causes and 11. Ponce de Leon, Dr. Gui, 2013, with PMA Consequences of Optimistic Time Mitigating the Planning Fallacy Consultants, LLC. Predictions, Hueristics and Biases (Risked Schedules - The New He can be - The Psychology of Intuitive Normal), 2013 NetPoint User contacted by Judgment, Pages 250-270, Conference Keynote sending e-mail to: Cambridge University Press. Presentation, PMA Technologies. [email protected] 6. Hadjichristidis, Constantinos; 12. Roy, Michael; and Nicholas Barbara Summers, and Kevin Christenfeld, 2007, Bias in Thomas, 2014, Unpacking Memory Predicts Bias in Estimates of Task Duration: The Estimation of Future Task Shannon A. Katt is Role of Typicality and Temporality, Duration, Journal of with PMA Journal of Experimental Social Experimental Psychology: Consultants, LLC. Psychology, Vol. 51, March 2014, Learning, Memory, and She can be Pages 45-50. Cognition, Vol. 35, No. 2, Pages contacted by 7. Kahneman, Daniel, 2011, Chapter 557-564. sending e-mail to: 23, The Outside View, Thinking, 13. Roy, Michael; Scott Mitten, and [email protected] Fast and Slow, First Edition, Pages Nicholas Christenfeld, 2008, 245-254, Farrar, Strauss and Correcting Memory Improves Giroux, New York. Accuracy of Predicted Task FOR OTHER RESOURCES 8. Kahneman, Daniel; and Amos Duration, Journal of For additional resources go to: Tversky, 1977, Intuitive Experimental Psychology: www.aacei.org/resources/vl/ Prediction: Biases and Corrective Applied, Vol. 14, No. 3, Pages 266- Do an “advanced search” by “au- Procedures, Technical Report 275. thor name” for an abstract listing of all other technical articles this author PTR-1042-7746, Defense 14. Vrable, Alina, 2013, Planning has published with AACE. Or, search Advanced Research Projects Fallacy: Why People Suck at by any total cost management subject Agency - Advanced Decision Planning, Sandglaz (web site area and retrieve a listing of all avail- Technology, Decision Research, blog), November 15, 2013, able AACE articles on your area of in- Eugene, OR. http://blog.sandglaz.com/. terest. AACE also offers pre-recorded 9. Klein, Gary, 2007, Performing a 15. Weick, Mario; and Ana Guinote, webinars, an Online Learning Center Project Premortem, Harvard 2010, How Long Will It Take? and other educational resources. Business Review, September Power Biases Time Prediction, Check out all of the available AACE re- 2007. Journal of Experimental Social sources. 10. LeBoeuf, Robyn; and Eldar Shafir, Psychology, Vol. 46, No. 4, Pages 2009, Anchoring on the “Here” 595-604. and “Now” in Time and Distance

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