The Critical Path – Precedence diagram method Luise Lorenz Christina Mohr.

The Critical Path – Precedence diagram method

Luise LorenzChristina Mohr

Critical Path Method (CPM)Project planning technique

Important tool for project management

For any project with interdependent activities

CPM helps you figure out:

how long a complex project will take to complete

which activities are critical◦those needed to be done in time in

order to follow the schedule

The model of CPM

1. A list of all activities required to complete a project

2. The duration of each activity has to be known

3. Analyze the dependencies between the activities

The model of CPMCPM calculates the longest path of

planned activities to the endEarliest and latest date that each

activity can start and finishAvoiding extension of the projectDetermining the ‚critical‘ activitiesActivities which have ‚total float‘

(delayed without making the project longer)

Critical pathSeries of project network activities which

lead to the longest overall durationShortest time to complete a projectDelay of critical activity has an impact

on the completion dateShorten the planned critical path by ‚fast

tracking‘ (more activities parallel) or ‚crashing the critical path‘ (shortening activities by adding resources)

Precendence diagram method (PDM)

Network diagram uses boxes to represent activities

Connection with arrows to show the dependencies

Early / late start dateEarly / late finish dateDuration

Advantages of PDMFinding the critical pathDefining the amount of time

requiredUsage to crash projectsTo reduce resourcesDefining dependenciesIdentifying lead and lag times

Design I

Operation Description

ES(Earliest Start)

EF(Earliest Finish)

Float

LF(Latest Finish)

LS(Latest Start)

Ref. No.Duration

if the float equals zero it‘s

considered critical

Design II

ES

LF

EF

LS Float

Duration

Operation Description

if the float equals zero it‘s

considered critical

Example

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