critical chain project management n notes

8/13/2019 Critical Chain Project Management n Notes

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Critical Chain Project

Management


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Contents

Definition Introduction

Difference from traditional project

management Challenges faced

Critical chain schedule

Buffer management

Methodology of CCPM

Benefits


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Critical chain project management

The Critical Chain Method is an outgrowth ofthe Theory of Constraints (TOC).

TOC focuses on identifying and fixing

bottlenecks in order to improve the throughputof the overall system.

Likewise ,Critical chain focuses on bottlenecks.

CCPM (Critical Chain Project Management) is a

new methodology for doing projects that allowsyou to complete projects with high qualitydeliverables in 10% to 50% less elapsed time,and/or 10% to 50% less resources (i.e. man-hrs,

$, etc.)


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Introduction With traditional project management methods,

30% of the lost time and resources are typicallyconsumed by wasteful techniques such as

bad multi-tasking

Student Syndrome In-box delays

and lack of prioritization.

Student Syndrome:refers to the phenomenathat many people will start to fully applythemselves to a task just at the time last possiblemoment before a deadline.


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Introduction

In project management, the critical chain is thesequence of both precedence and resourcedependent terminal elements that prevents aproject from being completed in a shorter time,given finite resources.

If resources are always available in unlimitedquantities, then a project's critical chain is

identical to its critical path.


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Differences

Starts tasks as soon aspredecessors are done,finishes tasks as quickly as

possible.

Starts and finishes tasks atscheduled start and finishtimes.

4

Emphasizes project progress.Emphasizes task progress.3

Protects overall projectcompletion with buffers.

Protects individual taskswith safety time.

2

Schedules average taskdurations.

Schedules worst-case taskdurations.

1

Critical Chain ProjectManagement

Traditional ProjectManagement

No


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Challenges facedIf there were a way of managing projects without task

due dates and the undesirable behaviors they instigate,it would have to deal with several non-trivialchallenges:

How can we systematically protect the promise date of

an entire project from Murphy and uncertainty withoutnailing all the tasks to deadlines on a calendar, whichbrings Parkinson and wasted safety time into thepicture?

How can we systematically take advantage of early

task finishes when they can help us to accelerate theproject and maybe allow us to finish it early, freeing upthe resources to address other projects?

How can we manage the execution of a project -- howdo we know what shape our project is in once it getsstarted, if we don't have due dates to track?


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Challenge 1:Achieving both speedand reliability

Three things can help avoid Parkinsons Law.1. Build the schedule with target durations that are

too tight to allow diversion of attention. CC methodologyrequires that the schedule be built with only the time to do

the work without safety. This is the time we expect thework to take if allowed to focus a full sustainable level ofeffort on it and if there are no significant problems.

2. Get rid of task due dates. For this we describe

estimates in terms of 50% confidence level. This leadsdirectly to elimination of due dates.

3.Charge management with responsibility to protectproject resources from interruptions rather than getting intheir way with unnecessary distractions.


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Challenge 2:Early finishes are tiedinto achieving speed

There are two steps to accomplish this:

Step1: Ask resources how much of an advance

warning they need to finish up their other work and

shift to interruptible work so that when precedingproject task is done they can stop what they are

doing and pick up their critical task.

Step2: Require resources to provide regular,

periodic updates of current estimate of time tocomplete their current task


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Rest of Challenge1: Dealing withMurphy s Law

But you are not yet done with 1stchallenge. Especially

the part about protecting against Murphys Law. Uptil

now weve got a tight schedule supported by these

resource alerts to assure critical resources are availablewhen needed and that they can pick up work when tasks

are finished earlier than expected. The problem is that

50% estimates do not do too much to help us promise

final due date of project. We need to protect due date

from variations in tasks esp. critical tasks.

Thus instead of spreading safety all around of the

project lets take a whole system view and concentrate

on where it will help us.


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Feeding buffer: concentrate the safety associated withchains of non-critical tasks (again, reduced due toaggregation) as a buffer protecting the start of the

critical chain task they feed into--"feeding buffers."Thus feeding, non critical tasks are two buffers awayfrom impacting project more. Also you gain more by

keeping non-critical chain resources focused on workat hand and to assure that they finish work that can be

passed onto other resources.Project Buffer: The safety associated with critical

tasks can be shifted to end of chain, protecting projectpromise from variation in critical chain tasks. This

concentrated aggregation of safety is calledPROJECT BUFFER.


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Challenge 3: Managing theexecution of projects

The key is the set of feeding and project buffersand a process known as "Buffer Management.

Buffers allow focus, simplify priorities and

provide early warning regarding health ofproject. Planning and action depend on howmuch buffer has been consumed or replenishedby task performance, which tell us when to act,

when to protect critical chain and projectpromises.


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Methodology

The contents of methodology of critical

chain project management are:

Planning

Execution

Monitoring


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Planning

Two duration are entered for each task

Best guess. The justification for using the 50% estimates is that half of the tasks will

finish early and half will finish late, so that the variance over the course of

the project should be zero.

Safe duration.

which should have higher probability of completion (perhaps 90% or 95%,depending on the amount of risk that the organization can accept).


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Execution

Competition of project. When the plan is complete and the project ready to kick off, the

project network is fixed and the buffers size is "locked" (i.e. theirplanned duration may not be altered during the project)

50%Task duration. task durations have been planned at the 50% probability

duration, there is pressure on the resources to complete criticalchain tasks as quickly as possible, overcoming student's syndromeand Parkinson's Law.

Parkinsonslaw. The goal, here, is to overcome the tendency to delay work or to do

extra work when there seemsto be time.


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Monitoring

Monitor the buffers.

we monitor the buffers that were created during the planning stage

creation of charts. A fever chart or similar graph can be easily created and posted to show the

consumption of buffer as a function of project completion

The project is on target.f the rate of buffer consumption is low,the project is on target. If the rate of consumption there is likely to be littleor no buffer at the end of the project,


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Benefits

Parkinson's Law. An aggressive target duration schedule, along with elimination

of task due-dates, minimizes impact of

"Parkinson's Law."Buffer Management

avoids unnecessary distraction, and allows recovery planning totake place when needed, but well before the project is in trouble

Resource alerts allow projects to take advantage of good luck and early task

finishes while buffers protect against bad luck and later thanscheduled finishes.


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Murphy's Law. Concentrate safety in strategic places that protect what is important

to the project from Murphy's Law

Parkinson's Law

Avoid task due-date focus and Parkinson's Law. Old habits are hardto break. Project managers must stop publishing date-laden projectschedules.

Multi-Tasking. Avoid resource multi-tasking and the lead-time multiplication it

results in. Focus on the task at hand.

Resource Contention. when building project schedules must realize resource

dependency is as real as task dependency when determining what iscritical for the project.

Achievements


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Mind Map Identify the constraints: The things that prevents the

organization from obtaining more of the goal. Decide how to exploit the constraints: make sure the

constraint is doing things that the constraint

uniquely does, and not doing the things that itshould not do. Subordinate all other processes to above decision:

align all other processes to the decision made above.

Elevate the constraints: if required, permanentlyincrease capacity of the constraint; buy more. If, as a result of these steps, the constraints has

moved, return to step1. Do not let inertia become the

constraint.


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Thank you!

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