6.3 Sequence Activities

Knowledge Area

Process

Initiating Planning ExecutingMonitoring &

ControlClosing

Time  

Plan Schedule management- Define Activities Estimate Activity Resources Sequence Activities Estimate Activity Durations Develop Schedule

  Control Schedule

 

Enter phase/Start project

Exit phase/End project

InitiatingProcesses

ClosingProcesses

PlanningProcesses

ExecutingProcesses

Monitoring &Controlling Processes

Now that we’ve identified the schedule activities, we

need to sequence them in a logical order and find out

whether dependencies exist among the activities.

The interactivity of logical relationships must be

sequenced correctly in order to facilitate the

development of a realistic, achievable project schedule

in a later process.

Consider a classic example. Let’s say

you’re going to build house.

• You must excavate before you can

build the foundations

• You must build the walls first

before you build the roof

• And so on…

During Sequence Activities, you will

use a host of inputs and tools and

techniques to produce the primary

output, project schedule network

diagrams.

Once you’ve identified the dependencies and assembled all the other inputs for the Sequence Activities process, you’ll take this information and produce a diagram or schematic display of the project activities.

The diagram or schematic display is called project schedule network diagram

Start End

Project network diagrams are schematic displays of the project’s activities and the logical relationships (dependencies) among them.

Show workflow from left to right.Not drawn to a time scale.Can vary in how detailed the diagram should be.

Network diagrams

Shows interdependencies of all activities

Show workflow so the project team will know what activities need to happen in a specific sequence

Aid in effectively planning, organizing and controlling the project

Compress the schedule (defined later) in planning and throughout the life of the project

Show project progress if used for Control Schedule and reporting

Help justify the time estimate for the project

How a network diagram helps a project?

6.3 Sequence Activities

Inputs

1.Schedule Management Plan

2.Activity list3.Activity

attributes4.Milestone list5.Project scope

statement6.Organizational

process assets

Tools & Techniques

1.Precedence Diagramming Method (PDM)

2.Dependency determination

3.Applying leads and lags

Outputs

1.Project schedule network diagrams

2.Project document updates

Inputs

1. Schedule Management Plan: Section 6.2

2. Activity list: Section 6.2

3. Activity attributes: Section 6.2

4. Milestone list: Section 6.2

5. Project scope statement

• Contains the product description that may indicate

sequencing of activities such as physical layouts,

interfaces, etc.

6. Organizational process assets

• Historical records form similar projects

Tools and Techniques

1. Dependency Determination

Dependencies are relationships between the activities in

which one activity is dependent on another to complete

an action, or perhaps an activity is dependent on

another to start an action before it can proceed.

Dependency Determination

1. Mandatory dependenciesAlso known as “hard logic” are inherent in the nature of the work being done; They often involve physical limitations.•Example: Complete the foundations before you start building the walls of a house

2. Discretionary dependenciesAlso known as “preferred” or “soft logic” are defined by the project team usually based on knowledge of:•“Best practices” within a particular area based on past experience or some unusual aspect of the project where a specific sequence is desired, even though there are other acceptable sequences.•Example: Complete Room 2 of a house before completing Room 1

3. External dependencies

•External dependencies are, well, external to the project.

This might seem obvious, but even though the dependency is

external to the project and therefore a non project activity, it

impacts project activities.

•For example, perhaps your project is researching and

marketing a new drug. The government must approve the

drug before it can be market it. This is not a project activity,

but the project cannot move forward until approval occurs.

That means government approval is an external dependency.

Dependency Determination

NOTEYou must determine all the

types of applicable

dependencies in the project in

order to sequence the

activities and subsequently

develop the project schedule

Tools and Techniques

2. Applying Leads and Lags

Activity dependencies may require a lead or a lag to

accurately define the activity logical relationship.

Lag

Inserted modification of logical dependency between

activities that allows for waiting time (delay) between

activities

• Example: In a finish to start dependency; “You must

wait 20 days after pouring concrete before you can

construct the house frame”

ConcreteConcrete

FrameFrame

ConcreteConcrete

FrameFrame

Lag = 20days

Before the Lag

After the Lag

Applying Leads and Lags

Lead

Inserted modification of a Finish to Start dependency

logical relationship that allows an acceleration of the

successor activity.

• Example: You can start the brick work on a house 10 days

before the entire wood frame is completed

Applying Leads and Lags..

Before lead

After Lead

Wood FrameWood Frame

Brick workBrick work

Wood FrameWood Frame

Brick workBrick work

Lead = 10 days

Applying Leads and Lags..

3. Precedence Diagram Method (PDM) or Activity on Node (AON):

This is a method of constructing a project network diagram that uses boxes or rectangles (nodes) to represent the activities and connects them with arrows that show the dependencies.

This is the method used by most project management software packages.

PDM/AON can be done manually or on a computer. Example:

start

A B C

D E F

Finish

Tools and Techniques

Precedence Diagram Method (PDM)

• Each activity is represented by a box.

• The activity description is written in the box.

• Each box is assigned a unique activity number.

• Activities have a precedential relationship (there are 4

types).

• Some activities may be done concurrently.

PDM/AON does not use

DUMMY arrows to connect

activities.

PDM/AON can only use one

time activity estimate (see

Estimate Activity

Durations ) to determine

project duration

Hint

Precedence relationshipsa. ) Finish-to-Start (FS):

AA

BB

In PDM diagrams, this is the most often used logical relationship.

This relationship says that the predecessor-or the “from” activity-must finish before the successor-or the “to” activity-can start.

In plain English,

Activity B cannot start until A finishes

Precedence Diagram Method (PDM)

b.) Start-to-Finish (SF)

The start-to-finish relationship says that the predecessor activity must start before the successor activity can finish.

Activity B cannot finish until A starts

This logical relationship is seldom used.

BB

AA

Precedence Diagram Method (PDM)..

c.) Finish-to-Finish (FF)

The finish-to-finish relationship says that the predecessor activity must finish before the successor activity finishes.

Activity B cannot finish until A finishes

AA

BB

Precedence Diagram Method (PDM)..

d.) Start-to-Start (SS)

I think you’re getting the hang of this. The start-to-start relationship says that the predecessor activity must start before the successive activity can start.

Activity B will start when A starts

AA

BB

Precedence Diagram Method (PDM)..

1. Project network diagrams PDM

2. Project Document Updates Activity list and Activity Attributes Updates

Keep in mind that the construction of these project schedule network diagrams might bring activities to light that were missed when defining the activity list, or it might make you break an activity down into two activities in places where you thought one activity might work.

If this is the case, you will produce both activity list updates based on this new information as well as activity attributes updates.

Risk register Chapter “ Project Risk Management”

Outputs

Project Schedule Network Diagram

Next Topic 6.4 Estimate Activity

Resources