CS 5150Software

EngineeringLecture 6

Project Management

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Administrivia

• Quizzes posted

• Feasibility study/plan due in a little over a week

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Classic Project Management Example: OS 360

• The OS for the IBM 360 was 2 years late

• Q: How does a project get 2 years behind schedule?

• A: One day at a time!

• Fred Brooks Jr, The Mythical Man Month

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“The Mythical Man Month”

• Adding more people to work on a task helps up to a point, then becomes counter-productive

• Adding people adds coordination overhead

• Some activities work best in a single mind

• Some tasks cannot be accelerated beyond some limit

• In software, productivity varies A LOT between developers

• Some studies found that the most productive are 5x faster than the “just adequate”

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The Goal of Project Management

• Give the team the best chance to finish a project

• on time

• on budget

• etc

• Provide visibility into how well things are going according to plan

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The Central Tension in Project Management

• Clients (or managers, or whoever) want to know:

• What will the functionality be?

• When will it be available?

• What will it cost?

• Examples:

• For products, marketing needs to how to sell the software

• For embedded systems, other teams need to coordinate development

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The Central Tension in Project Management

• BUT:

• Every software project is a special snowflake

• Time and cost estimates are notoriously inaccurate

• Almost always something changes about the specifications during development

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Typical Project Planning Experience

• Some big projects (e.g. product releases) some smaller project (e.g. “phase 1” contracts)

• For smaller projects, just create rough time estimates and judge whether they’re reasonable

• For larger projects, detailed planning with labor estimates and task dependencies

• Still usually off by quite a bit

• Unanticipated tasks

• Unanticipated work on planned tasks

• Unanticipated schedule conflicts

• Unanticipated life conflicts

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Conventional Software Project Management

• The scope of the project is defined early

• Development is divided into tasks and milestones

• Time and resource estimates are made

• Estimates are combined to create a schedule/plan

• Progress relative to the plan is monitored, perhaps weekly

• The plan is modified as inaccuracies in the estimates become evident

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Agile Project Management

• Planning is divided into high level release forecasting and low level detail planning

• Release planning is a best guess of what can be achieved in a sequence of time-boxes (sprints)

• For each time-box, small teams do detailed planning

• Release plan is updated to reflect sprint results

• Clients and developers share ownership of the release plan and choice of sprints

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Universal Aspects of Project Management

• Planning

• 5150: Rough plan for feasibility study

• More detailed plan for each milestone

• Progress tracking

• Regular comparison of plan and reality

• Update the plan!

• Occasional reassessment of project management processes

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Generating Time Estimates

• Developers are usually pretty good at estimating times for tasks within their areas of expertise, but ...

• Even so, little things get in the way

• The difference between “almost done” and “completely done”

• Unplanned technology churn

• There is always something that is a little bit different

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Team-based Estimation

• Developers themselves usually produce the best estimates within a small time window

• Teams can commit to the outcome of a sprint

• Still useful to have a local schedule/plan

• Different teams work at dramatically different rates

• Reminder: 5150 is about 1 sprint’s worth of development time

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Start-up Time

• Recruiting, tying up loose ends from previous projects

• Acquiring and setting up equipment

• Learning about new domains and frameworks

• Getting the ball rolling with clients/other collaborators

• Can be months for large projects

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Methods for Task-Based Project Planning

• Critical path method, Gantt charts, etc

• Build a work plan from task data/estimates

• Display plan in graphical and tabular forms

• Software support

• Spreadsheets/databases for recording estimates and results

• Fancier software for calculating estimates and generating reports

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Task-Based Project Planning Terminology

• Task/activity

• A part of a project that takes work/time

• Event

• The completion of a group of activities

• Dependency

• Constraints imposed on one activity by another

• Resource

• Staff time, equipment or other item required for a task

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Task-Based Project Planning Terminology

• Deliverable

• Any work product that is provided to clients or users (software, documentation, etc)

• Milestone

• A set of tasks, usually associated with a target date

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A Simple Gantt Chart

• (made with Microsoft Excel)

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Gantt Charts

• Most useful for small projects or pieces of larger projects

• Horizontal axis is time

• Each row is a task: (planned) start time, portion complete, (projected) completion time

• Progress can be tracked by drawing a vertical line at the current date

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A More Complex Gantt Chart

• (Made with SmartDraw)

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Alternative Visualization: Activity Graph

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Activity Graph Background

• PERT

• Program Evaluation and Review Technique introduced by the U.S. Navy in 1957 to support the development of its Polaris submarine missile program.

• PERT/Time

• Activity graph with three time estimates (shortest, most probable, longest) on each activity to compute schedules.

• PERT/Cost

• Added scheduling of resources (e.g., facilities, skilled people, etc.)

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Critical Path Method

• Uses and activity graph with a single time estimate for each task

• A standard method for managing large construction projects

• On big projects, activity graphs with 10,000+ tasks are common

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Step 1: Time Estimates

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Step 2: Earliest Dates

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Step 3: Latest Dates

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Step 4: Slack

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Step 5: Critical Path

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Feedback

• One of the latest trends in project management: evidence-based scheduling

• Developers generate estimates for all their tasks and record the actual time taken

• A learning algorithm adapts to each developer’s estimation strengths and weaknesses over time