S/W Project Management Software Project Planning (POMA) Task Analysis

S/W Project Management

Software Project Planning (POMA) Task Analysis

Agenda

Software Project Planning (POMA) Task Analysis

Work Breakdown Structure (WBS) Task Scheduling

Task Analysis & Scheduling

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Work Breakdown Structure

Is a depiction of the project (model) in terms of the discrete pieces of work needed to complete the project and the ordering of those pieces of work.

Performed by software project team.

Focuses on the tasks required to produce the artifacts that are to be delivered.


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As the details of the software development and support process are realized subtasks are identified.

There are a number of tools used to support the WBS activity: Graphical – MS Visio, Smartdraw, ArgoUML.

Scheduling – MS Project, Primavera TeamPlay


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Steps in the WBS:1. Examine the set of required external

deliverables.

2. Identify and list the steps and tasks needed to produce the required deliverables, including intermediate deliverables.

3. Sequence the identified tasks required to produce the deliverable.

4. Estimate the effort required to perform each task.

5. Estimate the productivity of the resources that will be applied to the tasks.


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Steps in the WBS:6. Compute the time needed for each task by

dividing the task effort estimates by the resource productivity estimates.

7. Lay out the time needed for each task and “label” each task with its task name and the assigned resources; this layout forms the initial schedule


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Identify and list all

deliverables

For each deliverable:Identify and list thenecessary tasks forcompleting the deliverable

For each task:Compute the timelinerequired by dividingeffort by productivity

For each task:Estimate the productivity of the assigned resources

For each task:Estimate the effort needed

Sequence the tasks

Lay out the timeline for allthe ordered tasks need for each deliverable

Perform task

After the timelinesfor all tasks for all deliverable are computed

Flow of WBS to schedule


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WBS - Example

Deliverable 1: Executable code that is installable from a CD.

Deliverable 2: Help text, usage, and reference information that is installable from CD.

Deliverable 1 activities: To develop code: requirements specification, and

analysis (which are already completed), design, coding, and testing.

To make code installable: requirements specification (already completed), design, coding and testingTask Analysis & Scheduling

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WBS - Example

Deliverable 2 activities: Creating help text: requirements specification

and analysis (already completed), design, writing, and testing.

Developing usage and reference information: requirements specification and analysis (already completed), design, writing, and testing.


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WBS - Example

Choice of activities and sequence depends on:1. The size and complexity of both the problem and

the solution,

2. The process and methodology that the software organization has defined and trained its people to follow, and agreed with its client to use.

Sequencing the activities needed for the development of the artifacts can be a large problem for new software organizations.


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WBS Task Refinement

List of activities for Deliverable 1: Activity A: Designing and documenting the design

using an agreed upon notation Activity B: Coding (in language agreed upon) Activity C: Defining test cases and generating test

scripts Activity D: Executing test scripts Activity E: Correcting and fixing problems found

during testing Activity F: Collecting the tested executable

modules and handing them to the packaging group


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WBS Task Refinement

Tasks Description

Task A-1 Overall application, user interface (UI), and message architecture

Task A-2 Database and relational tables design

Task A-3 Application function 1 design



Refinement of activity A:

Table 2.1. Subtasks within the Design activity


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WBS - Task Sequencing

After the tasks refinement then comes the sequencing of the tasks.

There are usually dependencies between tasks i.e., Task A-1 needs to be completed before Tasks A-2, A-3, A-4 and A-5 commence.

There may also be overlap between tasks, i.e., Task A-2 maybe or may not be started before Task A-1 is completed.


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Sequence diagrams depict the start-stop relationships among the various subtasks.

Sequence diagram – shows all the tasks required to complete an activity and the order in which those tasks must be performed, including the depiction of the tasks that may be performed in parallel.


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TaskA-1

TaskA-2

TaskA-3

TaskA-4

TaskA-5

Fig. 2.2 Sequence diagram

• Tasks A-3, A-4, and A-5 maybe performed in parallel.• Note there is no indication how task may overlap.


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Steps for the construction of the software project:1. List the deliverables.

2. For each deliverable, list the activities that are required.

3. For each activity, list the set of subtasks that are required.

4. Further refine any of the subtasks by creating the next level of subtasks, if necessary.

5. Construct the sequence relationship of the subtasks

6. Depict the sequence relationship with a sequence diagram


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WBS – Time and Resource Assignments

What is a “satisfactory” level of refinement?

Guidelines: Each task may be assigned to one person.

The estimate of the task cost, stated not in terms of money but rather in terms of time required to complete it, does not extend beyond more than two or three project status meeting.

Ensuring single person accountability makes the management and tracking of the task much easier.


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WBS – Time and Resource Assignments

Assume that project management meetings are conducted very often, daily, for a small project (range of weeks) and weekly if the s/w project is large (range of months < 1 year).

Units of tasks management: Project team must decide on a unit of

measurement, usually range from 1 hour units to a several days (< week).

It is important to state hours in a day and days in a week (5 or 7)


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WBS - Time and Resource Assignments

Units of tasks management: Time must be allocated for non-direct-task-

related activities e.g., departmental meetings, telephone interruptions etc.

How to estimate time required to complete a task.

Ask experienced s/w engineers (bottom-up estimating).

Assemble a team and ask them to estimate each task in terms of some common work volume unit e.g., lines of code (LOC) per hour per day


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Tasks Possible rates

Requirements elicitation 2 interviews/person-day

Message design 15 messages/person-day

Code implementation 2 functions points/person-day; 40 lines of Java/person-day

Test generation 5 test scenarios/person-day

Units of tasks management:

Example of Historical Information


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TaskA-1

TaskA-2

TaskA-3

TaskA-4

TaskA-5

End

5 days

3 days

3 days

3 days

7 days

5 days

2 days

Fig2.3 Subtasks with estimated times.

• Longest path includes A-1, A-2, and A-3 (critical path)• There is no slippage along the critical path.


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Estimates and assignments: Need to assign people to tasks.

1. Spmr need to consider skills required to perform each task, then seek people capable of performing these tasks.

2. Must consider the availability of the identified skilled people.

3. Must consider the timing of and the requirement of the identified person for another aspect of the project or another project.

The above must be made in conjunction with the schedule in the time-estimated WBS.


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Estimates and assignments cont:

The dependencies of the tasks in the WBS restrict assignment of resources, it also allows for the use of additional resources.

The skill of the team members may also restrict assignment.


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Subtask Person Sequence time-estimate

A-1 P1

A-2 P2

A-3 P3

A-4 P4

A-5 P5

Estimates and assignments:Subtasks with time Estimates and People Assignments

5 days

3 days

7 days

2 days

5 days


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Subtask Person Sequence time-estimate

A-1 P1

A-2 P2

A-3 P3

A-4 P4

A-5 P5

Milestones

5 days

3 days

7 days

2 days

5 days

Minor Milestone Milestone


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Milestones:

End-point of a software process activity.

A significant event in a project that occurs at a specific point in time.

The labeling of a milestone gives a certain amount of priority and significance to the event.

Spmr may use the term “milestone” to emphasize the particular activity, as well as for the purpose of recognizing the attainment of a significant task.


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Milestones: Depending on the size of the project the

schedule might only be depicted in terms of milestones. Such a schedule may be used by higher level management.

It is important for the spmr to recognize the accomplishments of milestones and publicly recognize them.

The spmr should also pay attention to missed milestones.


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Task Sequence and Effort representation

All tasks share at least two basic characteristics Require effort in terms of person-days required to

complete each task

A specified order for processing the task


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Task sequence/effort table

Task Immediate prerequisite tasks

Effort

(person-days)

A None 9

B A 5

C A 7

D B,C 11

E D 8

Total effort required: 40 person-days


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Graphical representation of tasks from previous table

Task A

Task B

Task C

Task D

Task E

End

Critical Task

Non-critical Task

Critical Path

Non-critical Path

9

9 5

7

11 8

Total project time: 35 days


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Critical versus Non-Critical Paths

Critical path The path that takes the most time to complete.

Critical task (critical activity) A task that resides on the critical path.

Non-critical path Any path that is not a critical path and thus takes less effort to

complete than the critical path.

Non-critical task (non-critical activity) Any activity that resides on a non-critical path and not a critical

path. These tasks may accept some delay in completion.


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Critical Path Method (CPM)

“The critical path method analyses the precedence of activities to predict the total project duration. The method calculates which sequence activities (path) has the least amount of flexibility ” Quality Software Project Management, Futrell et.

al.


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Task Scheduling

Forward-pass scheduling Early start time (ES) and early finish (EF)

Backward-pass scheduling Late start (LS) and Late finish (LF)

Slack time


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Forward-pass scheduling

Task Tasks precedence

Task length Earliest possible start

time (ES)

Earliest possible finish

time (EF)

A None 9 0

B A 5

C A 7

D B,C 11

E D 8

9

9 14

9 16

16 27

27 35


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Backward-pass scheduling

Task Tasks precedence

Task length Late start time (ES)

Late finish time (EF)

A None 9

B A 5

C A 7

D B,C 11

E D 8

9

11 16

9 16

16 27

27 35

0


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Slack time

Total slack time of an activity The difference in start time between a non-critical

task’s late start time and its early start time or its late finish time and early finish time.

Total slack time of a task = LS - ESOrTotal slack time of a task = LF – EFe.g., Activity B: LS – ES (11 - 9) or LF – EF (16 - 14) =>

2Total slack time

The maximum allowable delay for all non-critical activities.


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Program Evaluation and Review Technique (PERT)

An estimating techniqueassumes each activity duration is subject to a

range estimatesuses weighting method to arrive at a specific

duration.


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Expected estimate (EE) = [O + P + (4 x A)] / 6

WhereO = most optimistic estimateP = most pessimistic estimateA = most likely estimate


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Expected Project time (EPT)Sum of expected estimates of the critical

tasks.EPT = Σ(EE of all critical task)


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CPM vs PERT

Scheduling a lot of activities with 3 estimates computationally messy

many people argue 3 estimates are not much more accurate than 1 estimate

Most project management scheduling software use CPM


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Documents

S/W Project Management Software Project Planning (POMA) Task Analysis