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Work Breakdown Structures. Identifying Manageable Activities. Agenda. 1. Creating a WBS. 2. Using the WBS for Estimation. Work Breakdown Structure. Work A WBS considers the work that needs to be performed - PowerPoint PPT Presentation
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Project Management
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Work Breakdown Structures
Identifying Manageable Activities
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Agenda
1. Creating a WBS 1. Creating a WBS
2. Using the WBS for Estimation 2. Using the WBS for Estimation
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Work Breakdown Structure
• Work– A WBS considers the work that needs to be performed– This includes development, but also user manuals, sales support, administration,
deployment, media, etc.• Breakdown
– Work is broken down (decomposed) into small pieces (activities)– Activities are eventually broken down into tasks– A task is something that takes less than a week to complete– Activities are normally assigned to individuals
• Structure– Each unit of work is broken down into a number of components– The result is a hierarchical structure– The lowest layers are tasks
• e.g. A function that generates a polynomial collision-handling hash function is completed
• e.g. Send user manual prototype to printer for an estimate– The middle layers could be milestones
• e.g. “Getting started” tutorial is completed– The highest layers are normally deliverables
• e.g. Source code distribution, with configuration and makefiles, is completed
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Terminology
• Activity: – Some behaviour that needs to be done– Produces some outcome (e.g. a deliverable)– Is often decomposed into other activities or tasks
• Task:– An activity that is not decomposed– Is at the lowest level of the WBS– Also called a work package
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Example WBS
Usability Training
1 - Personnel Available
2 - Training Seminars Booked
57 - Hotel RoomsReserved …
……
2.1 - Deal Made with Susan Carleson
2.13 - Cheque RequisitionMade to Accounts Payable
2.2 - Budget ApprovalForm Submitted to Accounts Payable
…
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Advantages of a WBS
• The WBS:– Gives you a somewhat complete list of tasks
• Later, this can be a checklist to show how much is still to be done, and how much is done
– Allows you to easily assign work to team members– Requires you to solidify things that are still vague,
even after requirements analysis• Generating a WBS enables you to methodically decompose
the work, exposing new risks and resource requirements
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WBS Process Overview
• The WBS process is basically as follows:– The WBS is normally created from the top down– The estimates are created at the bottom– The estimates are summed from the bottom up– The totals at the top are used as input for the
schedule
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Creating a WBS: Top-down
• The top-down approach:– Start with the project’s overall goal– Decompose the goal into deliverables– Decompose the deliverables into modules …– When you are finished you have tasks
• Tasks should be a few days work or less
• This is an iterative technique to creating a WBS– In XP projects, the WBS iterations might produce only a part of
the next level while requirements are still being worked out– However, it should produce some tasks, so that work can begin
• It is a good idea to create the WBS as a group– This can prevent important activities from being missed, and can
add a level of peer evaluation to the process
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When is a WBS done?
• Since WBS is iterative, it could go on forever• There are guidelines for what is enough:
– Status/completion is measurable– The activity/task is bounded– The activity/task has a deliverable– Time and cost are easily estimated– Activity/task duration is within acceptable limits– Work assignments are independent
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Status/Completion is Measurable
• Project managers will ask team members about status– Status is generally how close they are to completion
• Activities:– Status of an activity is the ratio of completed tasks
• e.g. I’m finished 35 of 55 tasks, so I’m 64% done
– Completion of an activity is when all of its tasks are complete
• Tasks– Status of a task is generally small enough to estimate
• e.g. I’ve written all the code for the class, and just need to test it, so I’m about 50% done
– Completion of a task should take a few days or less
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The Activity/Task is Bounded
• The starting and ending points of an activity should be well-known– How do you get started on the activity? What task to do first?– How do you finish the activity? What is the last task to be done?
• e.g. Optimize the search engine– Tasks:
• Determine from customers the expected wait time• Measure existing search engine for comparison• Examine code for potential slowdowns• Make changes where possible• Investigate compiler options which could improve performance• Update build file to use new compiler options• Deploy search engine to test server• Measure new search engine performance• Verify that search engine meets customer criteria• Deploy search engine in public server• Ask customer for review and acceptance
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The Activity/Task Has a Deliverable
• All activities should produce something– High-level activities produce the deliverables outlined in the
requirements• e.g. Source code distribution, user manual, DVD media
– Lower-level activities can produce other ‘deliverables’• e.g. AI engine, device API for bar code readers, a customer class
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Time & Cost are Easily Estimated
• The less work is involved in an activity, the easier it is to estimate
• When we get down to task level, it should be possible to accurately estimate time and cost– Time: It is less work, so estimates should be accurate,
particularly when the task is similar to something else done recently
• e.g. Write the code to manage persistence of customers to/from the database
– This is similar to other persistent code you have (or will) write, so can be accurately estimated
– Cost: You will know if there are additional costs required• e.g. Licenses for an IDE, books, training
• We’ll deal with estimation separately
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Activity/Task Duration is Within Acceptable Limits
• Activities can take a very long time• However, tasks (the lowest level of decomposition)
should be limited in duration– Generally, less than 1-2 weeks is considered acceptable
• This is something that can be easily tracked• Also, if something goes wrong, things should not go to
far off track– e.g. A 5 day task takes 7 days to complete– e.g. A 10 day task was a waste of time, and needs to be re-
thought
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Work Assignments are Independent
• When a task is assigned to a team member, it should be possible for that team member to complete without further instructions– e.g. A team member should not be meeting daily with a manager
or customer while working on a 10 day task• A team member working on a task should have all they
need when they begin– A team member building on another task’s deliverables should
start the task after the other task’s deliverable is ready– e.g.
• A team member is working on improving the design for the 3D graphical engine
• When this is complete, another programmer might want to incorporate her code into the graphics engine
• This should not be done until the graphics engine is complete (with respect to the re-design)
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Common Sense with WBS
• Another way to ensure a WBS is complete is to use common sense
• If you were to tell a young child to brush their teeth, they might need more detailed instructions– Get your toothbrush and the toothpaste– Put a little bit of toothpaste on the toothbrush– Brush the front, back, tops, bottoms, and sides of your teeth– Spit into the sink– Rinse out your mouth with some water– Put away the toothbrush and toothpaste
• However, team members have done similar tasks before– If you say brush your teeth to an adult, they know what to do
• Not only is it a waste of time to go into more detail, it is also insulting • This is called micromanaging
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Activity/Task Names
• Activities and tasks should have active names:– e.g. Create a chart of search engine performance– e.g. Develop a sales pattern for the sales team– e.g. Establish a set of coding standards
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Task Sequencing
• In the WBS, tasks and activities are listed in chronological order where possible– e.g. In the setup development environment activity:
• ‘Purchase new computers’ must come before ‘Install IDE’
• However, specific task ordering will be done in the schedule later
Project Management
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Estimation
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How to Estimate Software
• How do you estimate how long it will take to develop a project?
• Let’s say you have an assignment due in 2 weeks– You want to decide when to work on it– You want to fit that into your schedule– To do so, you need to know how many hours it will
take
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Estimation
• Estimation involves using the following information in order to make an educated guess about time or resource requirements:– Knowledge of the work required (expertise)
• Ask people who know how long it should take
– Group knowledge• Coming up with estimates as a group is no substitute for expertise, but
sometimes expertise is not available• Advice from a group is generally more reliable than advice from an individual
– Prior experience• e.g. It previously took 8 minutes to copy, print, seal, stamp, and address
1000 brochures• It should take about 80 minutes to get 10,000 brochures ready
– Historical data• e.g. The team has worked on 3 other projects, which were all 25-50% over-
budget on time• Therefore, expect them to go over their own estimates by a similar factor
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Estimation
• Who creates estimates?– Technically, the project manager does– However, the PM is not an expert in all areas (e.g.
deliverables)• Thus, the ‘experts’ need to be consulted when creating
estimates• The experts are the people who might be asked to do the
work• It is wise to get a second (or third) opinion, to offset estimate
bloat and over-optimism• Estimates should start from the task level, since they are
easy to estimate
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Estimates as Ranges
• If you don’t know what the customer wants, so you can’t yet make an informed decision
This house shouldtake about 4 months
to build.
Good! We havea deal.
Contractor Customer
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Estimation Units
• There are several units in estimation:– Total time
• e.g. It should take 3-4 weeks, with a most likely estimate of 18 days• This makes it obvious when the project should be completed
– Human resource utilization (effort)• e.g. It should take 2-3 person-months, with a most likely estimate of 10
person-weeks• This way, you can see how adding people to the project will affect its
duration– Lines of code (size)
• e.g. It should be around 50,000 lines of code• This figure can then be used for other estimates, such as total time• However, few developers count lines of code anymore, so this is not very
common• Also, not all lines of code are created equal
– Function points (size/difficulty)• An estimate of the number of inputs, outputs, files, database tables, etc. that
an application will require• e.g. This should have 6 inputs of low complexity (x3), 2 inputs of medium
complexity (x4), and … for a 286 function point score
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Creating Estimates
• Estimates are created at the bottom, and work their way up– Tasks can be estimated easily
– The activity durations can be computing by taking the sum of the task durations
– This allows us to estimate activities that are cross-disciplinary
• However, minor deviations in task durations can quickly add up to major deviations in activity duration– This is exactly why you use an estimate range
– If your range includes the actual duration, it will be difficult to say that you were wrong
– Creating an accurate estimate from day one is impossible
Project Management
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Case Study
PathFinder 2.0
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Getting an Initial Estimate
Barb: Having gathered requirements for the
PathFinder 2.0 project, how long do you think
it will take?
Tyrone: I’ve been thinking about this quite a bit, and I’ve come up with about 4 months.
Barb: That long?! I told the board of directors it
would be ready in about a month!
Tyrone: We might be able to save some time here and there. Let me look at it again.
Barb: Good. Let’s aim for 1 month.
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After Some Thought…
• Having examined the project further, Tyrone was able to cut corners by shortening the design duration, but still not enough to fit the 1 month schedule
• However, Barb was so outraged by his original estimate, that he didn’t have the courage to say anything to her about the slip
• Perhaps the team will pull it together with the tighter budget
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3 Weeks Later
Tyrone: Barb, the team has been putting loads of
overtime into this project, but we’re not even
close to being finished. We just plain need
more time.
Barb: That’s disappointing Ty. Ok, let’s aim for 3
months total. That should be more than
enough time, given the extra hours your team
is putting in.
Tyrone: Yes, I think so.
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In the Meantime…
• Many aspects of the software have been hacks and the result is really ugly, low-quality code
• The code is being constantly re-worked due to the lack of a decent design
• The development is taking longer than expected, since team members have a tough time understanding the code with all the hacks and poor design
• However, since they are in such a rush, they do not feel there is enough time to fix the hacks or refactor the code to represent a better design
• The result is slow development and unreliable code• To meet the schedule, Tyrone increases development time well into
the QA time
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2 Months Later
Tyrone: We’re finished coding. This week will be for
quality assurance.
Barb: Good, but I thought that QA was scheduled
for 3 weeks?
Tyrone: It was, but we had to finish development.
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The result…
• The final code was very poor quality, due to:– Poor design
– Rushed development, which included many:• Bugs• Hacks
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The result…
• The reduced QA time meant that the team only found the most obvious bugs and were able to fix them by the deadline– When the customer saw the finished product, it crashed twice and
produced the wrong output on one occasion
– The customer requested that the project be more thoroughly tested
– After 6 more weeks, the product still had some bugs, but was finally useable
– However, the customer was no longer interested, since:• So much time had passed (5½ months), they lost interest• Market share had already been acquired by another competing product• They lost confidence in the team due to the poor quality product
– Not to mention management’s confidence in Tyrone• Is this entirely Tyrone’s fault?
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Summary :
• The creation of WBS has only a few rules :– It is created with the help of a team
– The 1st level is completed before the project is broken down further
– Each level of the WBS is a smaller segment of the level above
– Work towards the project deliverables
– Work not in the WBS is not part of the project
– Break down the project into work packages or activities that :• Can be realistically and confidently estimated• Cannot be logically further subdivided• Can be completed quickly (few days)• Have a meaningful conclusion and deliverable• Can be completed without interruption (without the need for more
information)
Project Management
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An Introduction
Planning & Scheduling
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What is a plan?
• A project plan is a network of dependent and independent tasks– A plan may also contain descriptions of persona
• A persona is a fictitious representation of a real person
– The plan may also include assignments of tasks to various persona
• An important part of the project plan is the network diagram, which shows task flow and task dependencies
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What is a schedule?
• A schedule is a description of start and end times for all the WBS’ tasks– The schedule accommodates the plan– The schedule specifies all dates in terms of offsets from the start
date– Ideally, the start date is a parameter which can be changed if the
project start is delayed• This way, real dates can be seen
• However, dates are not hardcoded so they can be easily changed
• An important part of the schedule is the Gantt chart
Project Management
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Planning
Planning & Scheduling
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Network Diagram
• A network diagram shows task/activity flow• Flow from one task to another may indicate:
– Dependencies between the tasks– Chronological ordering between the tasks
• Parallel task flows indicate task independence– It is not necessarily the case that tasks may be done in parallel,
but it is possible
Example :
BeginEnd
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Task/Activity Dependencies
• Finish to start: One task/activity must finish before the other task/activity can start– e.g. ‘Order PCs’ must finish before ‘Install IDE’ begins
• Start to start: One task/activity must have started before the other task/activity can start– e.g. ‘Design AI module’ must start before ‘Implement AI module’ begins
• Start to finish: One task/activity must start before another task/activity can finish– e.g. ‘Ensure successful handoff to Team B’ cannot finish until ‘Team B
begins work’
• Finish to finish: One task/activity must finish before another task/activity can finish– e.g. ‘User documentation screenshots’ must finish after ‘User interface
implementation’
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Network Diagram
• Many notations exist, but a UML behaviour diagram is common• Here is an example network diagram showing start to finish
dependencies
Collaborate with project managers to find availabletimes for employees
Make deal with Susan Carlson
Submit budget approval form to accounts payable
Finalize trip time with employees
Have employeessign waivers
Register for seminarson the finalized dates
…
…
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Personas
• A persona is a fictitious representation of a real person– e.g. Java Developer A– This could match either George Smith or Arin Kumal– The plan will not mention people by name, however
• A persona has certain skills– e.g. Familiar with OOP, Java, modular programming, coding
standards, documentation, etc.
• A persona can be assigned responsibilities, such as tasks from the WBS
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Why not use real names?
• People might not be available when the project begins– A project may go over schedule– Our project start may be delayed
• Replacement people will resent not being the first choice if they see the other names
• The fact is, many project managers create a plan with real people in mind– They may write out somewhere else who Java Developer I is,
and who Network Admin is, etc.
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Task Assignment
• Another part of the project plan is the task assignment– This includes a description of all team members
• These are normally personas
• The persona description will include a reasonable set of expected skills that the real person should have
– For each task, a team member is assigned
• This is done after the network diagram, so that work can be distributed evenly
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Task Assignment
• User interface expert• Java developer I• Java developer II• Database developer• Database admin• Server admin
Task Team Member
Create visual prototypes of the UI User interface expert
Write code to persist registration data Database developer
Write code to generate MD5 of password Java developer I
…etc…
Project Management
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Schedules
Planning & Scheduling
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Schedules
• A schedule is an implementation of the project plan– However, in industry lingo, a project plan document normally
includes the schedule
• A common schedule representation is a Gantt chart– A Gantt chart is a graphical depiction of the task flow, with dates– Dates are shown as the x-axis, so questions about start/end
times can be answered• e.g. Relative start times of parallel tasks• e.g. Completion of all of an activity’s tasks• e.g. Chronological dependencies between tasks
• However, other formats are possible:– A calendar, showing tasks started, active, and completing– A list of task descriptions, including start and expected end dates
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Gantt Charts
• Visual representation can help when a project manager needs an overview:
September October November December
User InterfacePrototype
RegistrationPersistence
Code to Gen. Password MD5
…etc…
RegistrationDialog
…etc…
Project Management
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A Practical Guide
Planning & Scheduling
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Creating a Schedule
• In practice, a PM will use a project management tool to do much of their work:– Microsoft Project– Gantt Project– Open Workbench– OmniPlan
• All of these applications let you easily create:– Gantt charts– Task descriptions– Calendar views
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Using Microsoft Project
• Using Microsoft Project to create a schedule is easy:• Step 1: Enter the tasks:
– Enter the task name
– Enter the start time
– Enter either the duration or expected end time
– Enter dependencies, if any
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Using Microsoft Project
• MS Project generates the Gantt chart for you automatically, on the right:
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Using Microsoft Project
• MS Project allows you to change dates whenever you want• Thus, you can push back the start date if the project is delayed• The entire schedule is shifted over in response• You can add/change dependencies as you wish as well• Next to tasks is a space for resources
– Here is one place where you could put in persona names• e.g. Java developer I
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Common Schedule Problems
• Problems with estimates or deadlines:– Customer or upper management set deadline without team consultation– Schedule is based on ‘best case’ estimates– Target date moved up without re-adjustment to scope, resources, or schedule
• Problems with requirements:– Schedule omits necessary tasks– Project size is impossible within allotted time– Project is larger than estimated– Effort is greater than estimated
• Problems with schedule management:– Schedule was based on specific team members that will not be available– Schedule slips are ignored when schedule is re-evaluated (velocity)– Delays in tasks result in delays in dependent tasks– Unfamiliar territory causes unexpected delays
• Problems with productivity:– Demotivated personnel (e.g. schedule pressure)– Weak personnel – Friction between team members