Explain like I'm five · SW Eng

What is a WBS?

The Work Breakdown Structure (WBS), told as a story about a publishing house splitting the goal of 'publish one book' into small tasks.

GOAL: publish one bookjust a goal — and no idea what to do first

There's just the goal: publish one book.Just a goal — and no idea what to do first.

no idea how long 'making a book' takesnot sure who's doing what, or if it's all on meas one big lump, 'making a book' has no clear timeline or owner

As one big lump, 'making a book' has no clear timeline or owner.There's no feel for how long 'making a book' even takes.

PUBLISH ONE BOOKwritingch. 1-5proofingprint and shipsplit tasks until each piece can be estimated and assignedWBS = the goal laid out as small tasks, branching like a tree

A WBS lays the goal out as small tasks, branching like a tree.Tasks get split until each piece can be estimated and assigned.

Split the big goalbranching it apart
Down to a work unituntil it can be estimated and assigned
Assign an ownerwho owns each branch
Check nothing's missingcounting branches to spot a missing task
WORK BREAKDOWNpublish one book└ writing (ch. 1-5)└ proofreading└ cover design└ printing└ distributionadd an owner and a timeline to each branch, and it becomes a schedule

Add an owner and a timeline to each branch, and it becomes a schedule.This tree is a WBS — the book's tasks laid out where everyone can see them.

splitting tasks without looking at order (dependencies)printing could get scheduled before proofingsplit too finely and there are too many branches to tracksplitting is just the start — order and the right granularity matter too

Split without looking at order, and printing can get scheduled before proofing.Splitting is just the start — order and the right granularity matter too.

In one breath

A WBS (Work Breakdown Structure) splits a big goal into task-sized pieces, laid out like a tree, so who does what and when becomes visible.

A WBS hierarchically decomposes a project's full scope into smaller work packages. The project goal sits at the top, broken down into sub-tasks until each is small enough to estimate and manage its schedule and cost. Schedule, owner, and cost get assigned to each resulting work package, forming the basis for schedule management (WBS feeding into a Gantt chart) and cost management.

When grown-ups say it

WBS
The goal laid out as a tree of tasks. Makes the full project scope visible.
Work Package
The smallest branch at the bottom of the WBS. This is where owner, timeline, and cost attach.
Gantt Chart
Bars drawn for each branch's timeline. A WBS with a schedule drawn on top.
Dependency
Printing can't start until proofing is done. Something splitting alone doesn't reveal.
IS Audit/PMO
Checking from the outside that the WBS is actually followed. Whether work follows the WBS is one of the things it checks. → the checker who watches the whole publishing run
Function Point
Gauging size first with the measuring ruler. Size is sometimes gauged before the WBS split even begins.
Technical Debt
A debt postponed under schedule pressure. Easy to accumulate when the WBS schedule slips. → the debt you pile up to move fast now
SLA
A promise to customers about service levels. A WBS breaks down project work; an SLA sets service levels in operation. They are different tools.
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