AMERICAN SPORTS BUILDERS ASSOCIATION CRITICAL PATH METHOD SCHEDULING FOR SUCCESS December 6-8, 2008 New Orleans, Louisiana Presented By: Bill Pronevitch

SCHEDULING- Is It Necessary? Effective Project Management involves coordinating activities such as: –Planning –Organizing –Controlling Time (scheduling) –Cost The “Scheduling” process forces people to: –Quantify their effort in discrete terms –Place tasks in proper relationships

SCHEDULING- Methodologies Two of the most common methodologies: –Bar Charts –Critical Path ADM: Arrow Diagramming Method PDM: Precedence Diagramming Method Both scheduling methods are widely used for: –Controlling –Making optimal use of project time

SCHEDULING- Bar Charts Bar Charts (also called “Gantt Charts”) are primarily for controlling Time elements: –Analyze/ specify the basic approach to be used –Segment the work into a reasonable number of activities that can be scheduled –Estimate the time required to perform each activity (i.e.- activity duration) –Place activities in “time-order” (logic) –Adjust the chart until the specified completion date, if one exists, is satisfied.

SCHEDULING- Bar Chart ABCDEFABCDEF Gantt Chart (Bar Chart) shows: All Activities and Status on a Single Chart

SCHEDULING- Bar Charts Benefits: –Plan, Schedule, and Progress on a single chart –A simple, understandable way to schedule small projects or undertakings Disadvantages: –Activity-limited, can’t handle complex projects –Doesn’t show logic ties (activity relationships) –Insufficient detail to enable timely detection of schedule slippages on long duration activities

SCHEDULING: Critical Path The Critical Path Method (CPM) was designed for and is useful on projects where the duration of each activity can be with reasonable certainty - it predicts project overall completion - it identifies the (critical) activities that control the overall length of the project CPM is widely used in: process industries construction and plant outages/ shutdowns.

SCHEDULING: Critical Path Benefits: –Determines shortest project completion time –Identifies “critical” activities – that can not be slipped or delayed (i.e.- “TOTAL FLOAT”) –Shows allowable slippage for “non-critical” activities (i.e.- “FREE FLOAT”) Disadvantages: –Large number of activities required –Difficult to read, understand, and maintain.

SCHEDULING: CPM/ADM ADM (Arrow Diagramming Method): –Arrow (line): represents an Activity –Tail (of arrow): shows an Activity’s start –Head (of arrow): shows an Activity’s finish –Node (or event): shown at each end The “Activity Number” consists of Head and Tail numbers, commonly referred to as I-J nodes (i.e.- “I-J Method” of CPM)

SCHEDULING: CPM/ADM ADM: Arrow Diagramming Method Process Work Order Requisition Material Install Pump Assign Crew (Dummy Activity – shows relationship, zero duration)

SCHEDULING: CPM/ADM Benefits: –Allows use of “Dummy Activities” which: Have a “ZERO” time duration Can be used to show additional relationships Disadvantages: –An Activity’s “Predecessor” must be complete before the Activity can start! –Neither the Activity’s “arrow length” or “arrow direction” have any meaning

SCHEDULING: CPM/PDM PDM (Precedence Diagramming Method): –Box/ Node: represents an Activity –Line/ Arrow: represents a Precedence – with time and direction properties Precedence consist of two parts: –“Relationship”: a Predecessor or Successor –“Lag”: the (positive or negative) number of work periods by which a specified Activity will be delayed (assumed to be “0” if not specified)

SCHEDULING: CPM/PDM PDM: Precedence Diagramming Method AC D E Process Work Order B Requisition Material Install Pump Assign Crew Pump Installation Completed

SCHEDULING: CPM/PDM Types of Relationships, Lags (aa,n): –FS, 0: Finish-to-Start, With “0 units” of delay –FF, 7: Finish-to-Finish, with “7 units” of delay –SS, 5: Start-to-Start, with “5 units” of delay –SF, 0: Start-to-Finish, with “0 units” of delay

SCHEDULING – PDM/ LOGIC Relationships (Logic Ties, Lags A B A B A B A B Start –to- Finish Finish -to- Finish Finish –to- Start Start –to- Start (FS,0) (FF,5) (SS,4) (SF,0)

SCHEDULING: CPM/PDM “6” Major Types of Constraints –Start On: a mandatory date –Start No Earlier Than*: can start “later” –Start No Later Than*: can start “earlier” – Finish On: a mandatory date –Finish No Earlier Than*: can finish “later” –Finish No Later Than*: can finish “earlier” * NOTE: Schedule logic drives “earlier” and “later” start and finish dates

SCHEDULING- PDM/ OTHER Hammock Activity –Spans many activities to show an “overall” performance period (i.e.- a summary activity) Logic Loop –One of the most common “scheduling errors” –Occurs when a set of activities precede each other in a “circular” fashion, (a group of activities can never begin nor end) –Must be eliminated prior to calculating the schedule (i.e.- running a time analysis)

SCHEDULING- Hammock PDM: Hammock (Summary) Activity A BC E D

SCHEDULING – PMD/LOOP LOOP: No beginning or end (a circular path) LOOP A BCD E F

SCHEDULING – PDM/ CALC’S Once a network has been created and the durations estimated for each activity, both the “Total Time” to reach project completion and each activity’s “individual” start and finish times, can be calculated –Manual computation is easy and logical (but tedious & time-consuming on large projects) Forward Pass: calculates early start/finish, (ES/EF) Backward Pass: calculates late start/finish, (LS/LF)

SCHEDULING – CALC’S FORWARD PASS: –Calculates “Earliest Start” and “Earliest Finish” times, observing the following rules: Assign an “ES” time to the first activity Other activities start as soon as their “predecessor” relationships have been satisfied Equations: –ES = EF (Pred.) + 1 –EF = ES + Duration - 1

SCHEDULING – CALC’S BACKWARD PASS: –Calculates “Latest Start” and “Latest Finish” times, observing the following rules: Assign an “EF” time to the last activity. All activities finish as soon as their “Successor” relationships have been satisfied. Equations: –LF = LS (Succ.) – 1 –LS = LF – Duration + 1

SCHEDULING – CALC’S PDM ACTIVITY NOTATION: –Activity Number: unique number to an activity –Duration: number of “work periods” assigned –ES & EF: calculated in Forward Pass –LS & LF: calculated in Backward Pass ACTIVITY NUMBER ES EF LSLF DURATION 1A5 357

Legend Activity ID ES Duration EF LS LF START FINISH FORWARD & BACKWARD PASS

Legend Activity ID ES Duration EF LS LF START FINISH FORWARD & BACKWARD PASS Early Dates: ESs = EFp + 1 EFs = ESs + Ds - 1

Legend Activity ID ES Duration EF LS LF START FINISH FORWARD & BACKWARD PASS Late Dates: LFp = LSs -1 LSp = LFp – D +1

Legend Activity ID ES Duration EF LS LF START FINISH FORWARD & BACKWARD PASS Late Dates: LFp = LSs -1 LSp = LFp – D +1

What is the Scheduling Process? Report/ Status Scheduling Planning

IDENTIFY MILESTONES Project Start Project Phase Start and Finishes Equipment and/ or Long Lead Item Delivery Project Finish

DEVELOP ACTIVITY LIST (EXAMPLE: HOUSE CONSTURCTION) Select Lot Clear and Grub Lot Install Utilities Construct House Select Contractors Arrange Financing Close Financing Landscape Purchase Appliance and Lighting Fixtures Install Flooring Paint

ASSIGN DURATION TO ACTIVITES (EXAMPLE: HOUSE CONSTRUCTION) Select Lot3 days Clear and Grub Lot10 days Install Utilities3 days Construct House60 days Select Contractors5 days Arrange Financing5 days Close Financing 1 day Landscape5 days Purchase Appliance/Lighting Fixtures1 day Install Flooring 5 days Paint5 days

SEQUENCE ACTIVITIES ASK THREE QUESTIONS! What activity must come before this one? What activity must come after this one? What activities can I perform at the same time?

REVIEW AND FINALIZE Review Relationships Review and Finalize Durations Review Resource Usage Review and Finalize Project End Date –Does this achieve the desired date? –If it does not…. What is the plan NOW?!?

SCHEDULING- CONCLUSION Planning and scheduling functions are usually performed iteratively in order to provide for accomplishing all required tasks within the specified time frames Both Critical Path Methods (ADM & PDM) create networks showing activity durations and total time for project completion “Failing to Plan is Planning to Fail”, hence “Plan the Work, Work the Plan”