Project Schedule with Precedence Diagramming Method (PDM)

The Precedence Diagramming Method (PDM) is a project management technique used in the scheduling of activities or tasks within a project. It is a graphical representation of the sequence of tasks needed to complete a project, showing the relationships between tasks and their dependencies.

Overview

Shows Activities in boxes or circles called nodesand connects the nodes with arrows.
Arrows/Lines represent the relationship and the dependencies of the work packages.
The activities are either successors or predecessors.

Types of PDM

Finish to Start

Describes the flow of work.
Activity A = Predecessor
Activity B = Successor
A has to finish so B can start.
e.g. You have to finish priming the wall so you can paint the wall.

Start to Start

A must start, so B can start.
Letting two activities start so they can work in parallel.
Typically, A will start a little bit before B.
e.g. once people log-in in their classroom computers, then the software updates will happen.

Finish to Finish

Two activities chase each other to finish
The engineer has to finish pulling the network cable so that the we can finish connecting the computers in the network.
Similar to Start to Start.

Start to Finish

Most unusual.
e.g. we have to put stickers on 10,000 bottles with 3000 at a time. You have to start producing the bottles in order to finish the inventory.

Creating Network Diagrams

Activity-on-Node (AON) diagram is a type of Network Diagram
Critical Path
The Critical Path is always the path with the longest duration.
The Critical Path determines the earliest completion date.

Here, C, D and E are activities, and the arrows show the flow of one activity to another.

Types of Float

Free Float

Project Float

Total Float

An activity can be delayed without delaying the early start of any successor activities.

Total Float

Project Float

Total Float

An activity can be delayed without delaying the project completion.

Project Float

A project can be delayed without passing the customer expected completion date.

Practicing a Float Diagram

Overview

Float means how much extra time we have for an activity. So if an activity has a float of 9, that means it has 9 extra days to finish that activity in without affecting the schedule of the activity immediately after it.

This is indicated in cell-5 of each activity nodes below.

Before PDM Analysis

After PDM Analysis

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