Slide 1Some Project Success StatisticsTheory of Constraints to the RescueWhat to Change?What to Change? Is Multitasking Beneficial?What to Change to?What to Change to?What to Change to?What to Change to?What to Change to?Let’s Consider an ExampleLet’s Apply CCPM to our ExampleLet’s Apply CCPM to our ExampleLet’s Apply CCPM to our ExampleUsing a Fever Chart to Track ProjectsSummary of the Critical Chain Approach1BA 341 – Lean OperationsDr. Bogdan BichescuCritical Chain Project ManagementSome Project Success StatisticsAccording to a 2015 Standish study218.00%53.00%29.00%Theory of Constraints to the RescueCritical ChainIntroduced by Eli Goldratt in The Critical Chain (1997)Challenges conventional project management approaches Relies on TOC principles to answer What to change?What to change to?How to cause the change?3What to Change?Deeply-rooted behavior associated with traditional project management practicesParkinson’s Law – Work expands to fill (and often exceed) the time allowedSandbagging – Early task completion does not get reportedStudent Syndrome - Always wait to the last minute to start a task4What to Change?Is Multitasking Beneficial?Multitasking implies starting work on a new task (project) before finishing the current oneAssume the example of 3 tasks that have to be executed by the same resource5A, 10 B, 8 C, 6A, 5 B, 4 C, 3 B, 4 C, 3A, 5When can task A be finished?How about now?6What to Change to?Use “Aggressive but Possible Times” (ABPT)Cut task durations in half Regular, safe duration estimateUse Aggressive but Possible Times (ABPT)What to Change to?Identify the Critical ChainThe longest sequence of dependent events that prevents the project from completing sooner, based on ABPT durationsThe correspondent of the “constraint” in a project environmentTask and resource dependencies are key in identifying the critical chain7What to Change to?Use Buffer Management, in the form ofProject Buffer Added at the end of the projectProtects final project completion date from variations in the duration of critical chain activitiesThe size of the buffer should equal about half of the safety removed from the tasks that make the critical chain, that is, half the length of the critical chain8Cr. Activity 1 Cr. Activity 2 Cr. Activity 3Project BufferWhat to Change to?Use Buffer Management, in the form ofFeeding BuffersPlaced at the merging points between a non-critical chain and the critical chainProtects the critical chain from variations in the duration of non-critical activities The size of the buffer should equal about half of the safety removed from the tasks that make that specific non-critical chain9Cr. Activity 1 Cr. Activity 2 Cr. Activity 3Non-cr. Activity Project BufferFeeding BufferWhat to Change to?Use buffer consumption to track project progressA function of the difference between the sum of actual completion times and sum of planned (ABPT) completion timesAvoid displaying milestones (ES, EF, LS, LF)Emphasize the “Relay Runner” work ethicAvoid using multitasking for capacity-constrained resources  don’t release projects as soon as soon as possible, when there is a capacity constraint10Let’s Consider an ExampleAssume the following project, where the letters represent resources and numbers activitiesFurther, assume that activity durations have been determined in the traditional wayi.e., have been individually padded for safety111V 12 days2W 12 days4Y 16 days5X 20 days3X 20 days6Z 24 daysEndStartLet’s Apply CCPM to our ExampleFirst, determine ABPTSecond, identify the critical chain (not required on final) 121V 6 days2W 6 days3X10 days6Z12 days5X10 days4Y8 daysEndStart1V 6 days2W 6 days3X10 days6Z12 days5X10 days4Y8 daysEndStartWhat is the expected project duration?Let’s Apply CCPM to our ExampleThird, add the Project and Feeding BuffersFourth, use buffer management to monitor project progressAssume that project is now at end of day 15, but task Y has just been finished Has any buffer time been consumed?131V 6 days2W 6 days3X10 days6Z12 days5X10 days4Y8 daysProject Buffer20 daysFB6 daysLet’s Apply CCPM to our ExampleUsing Buffer ManagementPercent buffer (project) consumption is7 days / (20 days) = 35%How do you feel about project progress to date?Should we be alarmed? 14Expected Variation Normal Variation Abnormal VariationReflects inherent task uncertainty. No intervention needed.While still reflective of normal task uncertainty, plans should be made to recover lost time, if project delayed to red zoneReflective of abnormal, special-cause variation. Corrective actions should be taken. 1/3 of Buffer 1/3 of Buffer 1/3 of BufferUsing a Fever Chart to Track Projects150% 100%Percent Project CompletedPercent Buffer Consumed0% 100%Carry on with the projectMonitorIdentify and solve problems16Summary of the Critical Chain Approach1) Use Aggressive but Possible Times (ABPT) for task durations2) Identify the Critical Chain by taking into account resource dependencies 3) Use Buffer Management to track project progress4) Avoid Multitasking when faced with a capacity