Precedence Diagramming

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    Precedence Diagramming

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    Work Breakdown Structure (WBS)A deliverable oriented hierarchical decomposition of the work to be executed

    by the project team to accomplish the team mission and create the required

    deliverables. The WBS defines the project scope.

    Scheduling Terminology

    Team Mission

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    DeliverableAny unique and verifiable product or result that must be produced to

    complete a project. Usually the lowest level of the WBS.

    Scheduling Terminology

    Team Mission

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    Scheduled Activity (task)A component of work performed to create a deliverable.

    Scheduling Terminology

    Team Mission

    Task 1

    Task 2

    (Etc.)

    Task 1

    Task 2

    (Etc.)

    Task 1

    Task 2

    (Etc.)

    Task 1

    Task 2

    (Etc.)

    Task 1

    Task 2

    (Etc.)

    Task 1

    Task 2

    (Etc.)

    WBS

    (Scope)

    A

    ctivityList

    (Schedule)

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    DurationTotal number of work periods required to complete a scheduled activity.Usually expressed as workdays. (contrast with effort)

    EffortTotal number of labor units requird to complete a scheduled activity.

    Usually expressed as staff hours or a rate. (contrast with duration)

    Schedule MilestoneA significant event in the project schedule, such as an event restrainingfuture work or marking the completion of a major deliverable. A measuring

    point. Milestones have 0 (zero) duration and no resource assignments.

    Scheduling Terminology

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    Basic Bar Chart

    (Gantt Chart)

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    Defining Activities/Tasks

    Definition

    Assignment

    Significance

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    Task InterdependenciesSpecify Task Relationships

    All tasks are Related To:

    Other Schedule Activities

    Mandatory or Hard Logic

    Discretionary or Soft Logic

    External Events

    Dependent Dates

    Required Dates

    Network Diagram

    Task Interdependencies

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    FS

    Finish Start

    Start

    Finish

    SSStart Start

    FFFinish Finish

    Start

    Finish

    Types of Task Relationships

    Finish Start

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    Lead and Lag are used to Modify Relationships Lead and Lag Can be used with any Relationship Type

    (FS, FF, SS)

    NormalFinish - Start

    Leads and Lags

    FinishStartModified by a Lead

    FinishStartModified by a Lag

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    Arrow Diagram Method (ADM)(aka Activity on ArrowAOA)

    Tasks represented by arrows (length not related to duration)

    Dependency shown as node

    Only F-S relationship used

    Archaic

    not used with current software

    1

    2

    6

    7

    8

    3

    5

    4

    Dummy task used to complete logic, duration of 0

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    Precedence Diagram Method

    (PDM)(aka Activity on NodeAON and Network Diagram)

    Tasks represented by nodes

    Dependency shown as arrows or links between nodes

    All task relationships can be used (FS, FF, SS)

    Basis for all current software applications

    A

    B

    C

    D

    E

    F

    G

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    Critical Path

    Sequence of scheduled activities that determines the projectduration

    Longest duration path through the project network

    Activities on the Critical Path are called Critical Activities

    Critical activities have no float or slack

    A project can have more than one critical path

    Activities not on the Critical Path are called Non Critical

    Activities

    To shorten the project duration, a scheduler must modify the

    critical path activities or dependencies

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    Total Floatthe total amount of time through a path of

    activities that may be delayed or extended without delayingthe project end date or violating a schedule constraint.

    Free Floatthe amount of time within an activity (ormilestone) tha can be delayed without delaying the start of the

    next activity in the network.

    Negative Floatthe amount of time that by which a critical

    activity (or milestone) misses a required date.

    Float (or Slack)

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    Critical Path Method

    1. Calculate Early Start & Early Finishdates (FORWARD PASS)

    2. Calculate Late Start & Late Finish dates(BACKWARD PASS)

    3. Calculate TOTAL FLOAT for each

    activity4. Identify activities with 0 (zero) TOTALFLOAT

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    16Activity Node

    WBS Code Activity

    Late Start (LS)

    Late Finish (LF)

    Early Start (ES)

    Early Finish (EF)

    Total Float (TF)

    Duration

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    Activity AWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    7

    Activity BWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    5

    Activity CWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    2

    Activity DWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    Activity EWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    Simple Project consisting of 5 Tasks

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    Activity AWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    7

    Activity EWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    TWO THINGS

    NEEDED TO SET

    PROJECT START& END DATE

    1. First and last activities

    (milestones)

    2. Activity durations

    1

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    Critical Path Method

    1. Calculate Early Start & Early Finishdates (FORWARD PASS)

    2. Calculate Late Start & Late Finish dates(BACKWARD PASS)

    3. Calculate TOTAL FLOAT for eachactivity

    4. Identify activities with 0 (zero) TOTALFLOAT

    6

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    Activity AWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    7

    Activity BWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    5

    Activity CWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    2

    Activity DWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    Activity EWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    Project Start Date & Task Durations are known

    1

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    Activity AWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    7

    Activity BWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    5

    Activity CWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    2

    Activity DWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    Activity EWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    3

    Early Finish = Early Start + Duration

    18

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    Activity AWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    7

    Activity BWBS Code Activity

    Early Start (ES)

    Early Finish (EF)

    Late Start (LS)

    Late Finish (LF)

    Duration

    Total Float (TF) =

    5

    Activity C

    WBS Code Activity

    Early Start (ES)