Rights Reserved 1 CPM-200: Principles of Schedule Management 15 th Annual International Integrated Program Management Conference November 16-19, Tyson’s Corner Virginia Professional Education Program (Training Track) presented by PMI-College of Performance Management faculty Lesson B : Critical Path Scheduling Techniques Instructor L. Sue Cooper

Rights Reserved 2 Schedules - Foundation of EVMS SCOPE ( Technical ) Period of Performance SCHEDULE ( Time ) BUDGET / COST ( Resources ) $$ $$ $$ $ $ Schedules must be interrelated with scope and cost. All three pieces must be accurate to maintain an integrated baseline for successfully completing a given job. The products/services the contractor has agreed to provide The planned/actual expenditure of resources

Rights Reserved 3 Objectives  The objectives of this presentation are to discuss the –Scheduling Process Understanding of the schedule development process and the importance of a valid schedule –Developing a Schedule Network How to construct a Precedence Diagramming Method (PDM) logic network The different types of relationships between activities –Network Calculations Define the meaning of critical path Identification of the schedule critical path How to calculate total float and free float The difference between total and free float –Schedule Baseline Understand why a baseline is necessary Baseline change approvals –Status Updates Accomplishment versus forecast –Schedule Traceability Definitions Importance

Rights Reserved 4 Schedule Topics  Scheduling Process  Developing a Schedule Network  Network Calculations –Critical Path –Total Float –Free Float  Schedule Baseline  Status Updates  Schedule Traceability

Rights Reserved 5 Planning/Scheduling  Planning (Think) –Defines the activities involved in the project, their logical sequence, and their interrelationships  Scheduling (Do it) –Places the project and each of its activities in a workable timetable

Rights Reserved 6 The Scheduling Process  Define the objective – think  Establish the organizational structure – think  Establish the key milestones required to satisfy the objective – think  Put key milestones in order of occurrence – schedule  Define the activities required to accomplish the work – think  Establish the logical relationships of the activities – Calculate/analyze – schedule  Estimate the duration of each activity – think  Validate technical content, identify risks –Make adjustments, as appropriate - think/schedule  Commitment and approval

Rights Reserved 7 Importance to Program Management  Common tool for project communication  Schedule baseline development  Critical path identification/analysis  A “snapshot” of program accomplishment to date  A look ahead at the forecast of completion  Basis for EAC development  Schedule risk analysis  “What if” analysis tool

Rights Reserved 8 Precedence Diagramming Method (PDM)

Rights Reserved 9 Developing a Schedule Network  A graphical representation of a project showing interrelationships of activities  When time estimates and computations are added – become the project schedule B C D F G H I A E J

Rights Reserved 10 E Design Drawings P Planning 10 Logical link to other tasks Engineering WBS No. First Engineering task in the schedule for WBS 1011 = 01 Developing a Schedule Network  Activities must be coded so they can be easily identified and found in the schedule database  Every activity must have –Brief description –Duration –Relationship to other activities in the schedule  Smart Codes add capability 5

Rights Reserved 11 A 01 a 10 Complete Staffing 10 Logical link to other tasks IMP Event Accomplishment Criteria Developing a Schedule Network  IMP example –Event A, Post Award Conference –Accomplishment 01, IPTs staffed and chartered –Criteria a, IPT Contractor/Govt Team Members Identified –Task No., Supporting Tasks 5 Task Number A01a 20 Identify SPO Team

Rights Reserved 12 Developing a Schedule Network –Predecessor Activity Code –Successor Activity Code –Relationship Start-to-Start (SS) Finish-to-Start (FS) Finish-to-Finish (FF) –Lag All tasks must have the Predecessor/Successors identified Design Drawings PlanningTooling Engineering Drawing Release Complete Predecessor Activity Successor ER

Rights Reserved 13 * Finish-to-Start Finish-to-Finish Start-to-Start B cannot start until A finishes B cannot finish until A finishes B cannot start until A starts * Most commonly used % of the relationships in a network are FS AB A B A B Developing a Schedule Network Relationship types

Rights Reserved 14 Let ’ s Create a Network  Task A initiates the project  Task A precedes tasks B, C and D  Tasks B and C precedes E  Tasks C and D precede task F  Tasks E and F precede task G  Task G completes the project Task A

Rights Reserved 15 A D C B F E G Let ’ s Build a Network

Rights Reserved 16 A D C B F E G Determine Durations ATP Contract Complete How long will each activity take to complete?

Rights Reserved 17 Total Float Free Float Project Duration Early Dates Late Dates Critical Path Method ATP Contract Complete

Rights Reserved 18 Critical Path Method  Critical Path Method (CPM) –A scheduling technique that defines all project activities and their interrelationships  Critical Path (calculated) –Longest path of logically related activities through the network which has the “least” Total Float –Defines project duration

Rights Reserved 19 Critical Path Duration = 25 Time Units Path A-B-D-H = 19 Time Units Path A-F-G-H = 22 Time Units Critical Path (25 Time Units) Calculating the Critical Path A 3 F 6 B 5 G 6 D 4 C 6 E 4 H 7 Add up the durations along each path to Contract Complete ATP Contract Complete

Rights Reserved 20 Network Calculations  Forward Pass –Calculates the earliest an activity can be done based on the logical relationships and durations –Identifies the longest path through the network which is the ‘critical path’ –Every activity will have an Early Start (ES) and an Early Finish (EF) when the forward pass is complete  Backward Pass –Calculates the latest a task can be done based on the logical relationships and durations before affecting the end date –Every activity will have a Late Start (LS) and a Late Finish (LF) when the backward pass is complete  To calculate the Total Float the Forward and Backward pass must be complete

Rights Reserved 21 ES + Duration -1 = EF Adding activity duration to Early Start gives Early Finish Produces Early Start Early Finish for each activity 3 3 Network Calculations–Forward Pass ES EF

Rights Reserved 22 Forward Pass A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start 1 1 Start with day 1

Rights Reserved 23 Forward Pass A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start Day 1 plus 6, -1 = 6 Next activity starts on the next day Every activity has an Early Start and an Early Finish ES EF

Rights Reserved 24 Network Calculations–Backward Pass LS = LF - Duration + 1 Subtracting activity duration to Late Finish gives Late Start Produces Late Start Late Finish for each activity LS LF

Rights Reserved 25 Network Calculations–Backward Pass A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start 22 Start with the latest Early Finish (EF)

Rights Reserved 26 Network Calculations–Total Float A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start Late Finish – duration + 1 The LF of the preceding activity is one day earlier

Rights Reserved 27 Network Calculations–Total Float The amount of time an activity can be delayed or expanded before it impacts the project end date. Difference between Early Finish and Late Finish calculates Float. ES EF LF LS

Rights Reserved 28 The amount of time an activity can be delayed or expanded before it impacts the next activity. Difference between the early start of the next activity minus the early finish of the preceding activity (minus 1) defines free float. D FF = 0 F FF = 0 G E FF = 2 5 EF = 8 ES = 11 EF = Will occur only when multiple activities constrain a single activity. 25 Network Calculations–Free Float

Rights Reserved 29 Network Calculations –Total Float 7

Rights Reserved 30 Is there any ‘Free Float’ in this network? Network Calculations - Total Float A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start TF = 0 TF = 6 TF = 0 TF = 8 48

Rights Reserved 31 Is there any ‘Free Float’ in this network? Look at E & G Look At G & H Network Calculations – Free Float A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start TF = 0 FF = 6 TF = 6 TF = 0 FF = 2 TF = 8 48

Rights Reserved 32 Notice – The Critical Path is also the path with the least amount of float Network Calculations -Total Float A 6 F 9 B 3 G 4 D 7 C 5 E 5 H 2 0 Start TF = 0 TF = 6 TF = 0 TF = 8 48

Rights Reserved 33 PrecedingSucceedingActivity ActivityActivity ActivityDurationStart Complete AB, F3Apr 1Apr 5 BAC, D5Apr 6Apr 10 CBE6Apr 11Apr 16 DBH4Apr 11Apr 14 E CH4Apr 17Apr 20 FAG6Apr 6Apr 11 GFH6Apr 12Apr 17 H D, E, G7Apr 21Apr 27 Network Calculations – Calendar Look at activity A – Duration of 3 with a start of Apr 1 & complete Apr 5????

Rights Reserved 34 Non work days Next activity starts on the first instant of next day Activity starts on the first instant of Day 1 Network Calculations–Calendar Duration Start Complete Activity A 3 Apr 1 Apr ThuFriSatSunMonTue

Rights Reserved 35 Time Phased Bar Chart

Rights Reserved 36 Critical Path Definitions  Critical Path is the longest path  The path that defines minimum project time –The path with the least amount of float –The path on which any activity expansion/delay lengthens the duration of the project  Total Float –The amount of time an activity can move with out impacting the end date  Free Float –The amount of time an activity can move with out impacting another activity

Rights Reserved 37 Schedule Baseline  A coordinated and approved schedule/plan.  Used to measure status against.  When integrated with cost the result is the Performance Measurement Baseline (PMB)

Rights Reserved 38 Schedule Baseline  Schedule Baseline can change as a result of: –Contract Change Orders –Customer Redirection –Internal Replanning –Formal Reprogramming  Baseline changes require formal authorization

Rights Reserved 39 Status Updates  Identify completed tasks  Identify and status activities in process (remaining duration)  Identify estimated start dates for tasks which were scheduled to have started prior to report date but have not  Check for activities worked out of sequence Status updates do not require formal approval

Rights Reserved 40 Measured against the approved baseline schedule STEP 1. HOW MUCH WORK WAS ACCOMPLISHED? STEP 2. WHEN WILL THE WORK COMPLETE? (Accomplishment) Time Now (Forecast Completion Date) Status Updates

Rights Reserved 41 Status Updates  Time now  Actual dates: –Start date –Finish date  Accomplishment  Remaining duration (how long it will take to finish) What do I need to know to ‘status’ the schedule?

Rights Reserved 42 Status Updates  Determine a “forecast” start or finish –For activities started but not finished: Remaining duration, how much longer will it take to complete the work –For activities scheduled to finish but are behind schedule: Remaining duration Assess the impact to succeeding activities in the network –For activities not started: Impact of preceding activities Assess the impact to succeeding activities in the network

Rights Reserved 43  Requires program coordination between IPTs and Scheduler  Forecast dates on the schedule must be consistent with time phased “Estimate To Complete” (ETC)  Status continues against the baseline schedule A recovery plan does not replace the baseline schedule. Tasks may be re-sequenced, resources realigned, or effort redirected to reduce the current behind schedule conditions to the maximum extent possible. Currently behind schedule but the baseline completion date will be met. Time Now Baseline completion date will not be met. The ETC phasing should be consistent with the schedule forecast dates Recovery Plan

Rights Reserved 44 Status Updates

Rights Reserved 45 Schedule Traceability

Rights Reserved 46 Schedule Traceability  The ability to readily track schedule dates, durations, status and revisions at all levels of schedule detail and between schedules at the same level of detail –Horizontal Traceability –Vertical Traceability

Rights Reserved 47 Schedule Traceability  Horizontal Traceability –A schedule dependency between performing organization –Hand-offs between organizations, teammates, subcontractors –Activities are dependent upon a preceding activity Predecessors have been identified Successors have been identified

Rights Reserved 48 Horizontal Traceability Design Start Section Release Eng Release Delivery FabTooling ProcurementPlanning Engineering Manufacturing Assembly ATP What does it look like?

Rights Reserved 49 Vertical Traceability  A relationship between different levels of schedule detail –All milestones that appear on a higher level schedule must be supported by the lower level schedules –Higher level schedules typically constrain lower level schedules –Different levels schedules must be linked by reference –All levels of schedules must be integrated

Rights Reserved 50 Vertical Traceability Mech System Thrust Structure Ctr Bod y Str Propulsion System Avionics System Engine System Thermal System Intermediate Schedule WBS Level 2 WBS Level Common Booster Core Tank Assy What does it look like?

Rights Reserved 51 Schedule Traceability  Hand offs between organizations not properly coordinated or formalized (horizontal)  Level of detail schedules are not consistent  No top down schedule direction  No formalized process for linkage or roll-up

Rights Reserved 52 Schedule Traceability  To achieve schedule traceability a formalized scheduling process must be in place for all ‘players’ –Common use of data fields by all participants –Utilization of same processing cycle –Disciplined status collection –Disciplined Baseline change control  Strong interdivisional/functional coordination  Strong management support