Break Down Epics into Tasks | 1-3 Day Story Sizing

Decompose epics into 1-3 day tasks using GitScrum's parent-child relationships. Story mapping and hierarchical views show progress. Smaller tasks = better estimates.

5 min read

Large epics are the enemy of flow. When work is too big, it's hard to estimate, track, and complete. Breaking epics into manageable tasks enables better planning, clearer progress visibility, and faster delivery. GitScrum's task hierarchy supports effective decomposition.

Why Break Down Epics

Large Epics	Decomposed Tasks
Hard to estimate	Estimable in hours/days
No visible progress	Daily completions
Blocked by dependencies	Parallel work possible
All-or-nothing delivery	Incremental value
Overwhelming	Achievable

Decomposition Techniques

Vertical Slicing

VERTICAL SLICE APPROACH
═══════════════════════

BAD (Horizontal/Layer):
───────────────────────
Epic: User Authentication

Task 1: Design database schema (2 weeks)
Task 2: Build backend API (2 weeks)
Task 3: Create frontend UI (2 weeks)
Task 4: Integration testing (1 week)

Problem: No value until week 7

GOOD (Vertical Slice):
──────────────────────
Epic: User Authentication

Slice 1: Email/password login (3 days)
  └── DB + API + UI + Tests for basic login

Slice 2: Password reset (2 days)
  └── DB + API + UI + Tests for reset flow

Slice 3: Remember me (1 day)
  └── DB + API + UI + Tests for persistence

Slice 4: OAuth login (3 days)
  └── DB + API + UI + Tests for Google/GitHub

Value: Login working after 3 days!

INVEST Criteria

INVEST CHECKLIST
════════════════

For each task, verify:

I - Independent
    Can be worked on without blocking others

N - Negotiable
    Details can be discussed, not rigid spec

V - Valuable
    Delivers something useful when done

E - Estimable
    Team can estimate the effort

S - Small
    Completable in 1-3 days

T - Testable
    Clear criteria for "done"

If any fail → Break down further

Story Mapping

STORY MAP STRUCTURE
═══════════════════

USER JOURNEY (left to right)
────────────────────────────
Visit    →  Sign Up  →  Setup    →  Use       →  Manage
Site         Account     Profile     Features     Account

PRIORITY (top to bottom)
────────────────────────

MVP:     [Landing]  [Register]  [Basic]   [Core]     [Logout]
           Page      Email       Name      Feature

V1.1:    [About]   [OAuth]     [Avatar]  [Advanced] [Settings]
           Page     Login                  Feature

V1.2:    [Blog]    [Invite]    [Prefs]   [Premium]  [Billing]
                    Team                   Feature

GitScrum Implementation

Task Hierarchy

TASK STRUCTURE IN GITSCRUM
══════════════════════════

EPIC (using label + parent task):
├── Label: epic:user-auth
├── Parent Task: "User Authentication System"
│
├── Story: "Email/Password Login"
│   ├── Task: Create users table migration
│   ├── Task: Build login API endpoint
│   ├── Task: Create login form component
│   ├── Task: Add form validation
│   ├── Task: Implement session management
│   └── Task: Write login tests
│
├── Story: "Password Reset"
│   ├── Task: Add reset token to schema
│   ├── Task: Build reset request endpoint
│   ├── Task: Create reset email template
│   ├── Task: Build reset form
│   └── Task: Write reset flow tests
│
└── Story: "OAuth Login"
    ├── Task: Configure OAuth providers
    ├── Task: Build OAuth callback handler
    ├── Task: Create OAuth button components
    └── Task: Write OAuth tests

Progress Tracking

EPIC PROGRESS VIEW
══════════════════

User Authentication System
──────────────────────────
Progress: ████████░░ 75%

Stories:
├── Email/Password Login   ████████████ 100% ✓
├── Password Reset         ████████░░░░ 67%
├── OAuth Login           ████░░░░░░░░ 33%
└── Two-Factor Auth       ░░░░░░░░░░░░ 0%

Completed: 15/20 tasks
This Sprint: 5 tasks remaining

Decomposition Workshop

Team Exercise

EPIC BREAKDOWN SESSION
══════════════════════

DURATION: 30-60 minutes

1. UNDERSTAND (10 min)
   ├── What is the epic?
   ├── Who is the user?
   └── What's the goal?

2. MAP (15 min)
   ├── Draw user journey
   ├── Identify major steps
   └── Group by functionality

3. SLICE (20 min)
   ├── Identify MVP slice
   ├── Break into stories
   ├── Further break into tasks
   └── Apply INVEST criteria

4. ESTIMATE (10 min)
   ├── Quick sizing (S/M/L)
   ├── Identify unknowns
   └── Flag risks

OUTPUT:
├── Prioritized story list
├── Tasks per story
└── First sprint scope

Common Patterns

By Technical Area

DECOMPOSITION PATTERNS
══════════════════════

CRUD OPERATIONS:
├── Create functionality
├── Read/List functionality
├── Update functionality
├── Delete functionality
└── Validation & error handling

USER FLOWS:
├── Happy path
├── Error states
├── Edge cases
├── Loading states
└── Empty states

INTEGRATION:
├── API contract definition
├── Implementation
├── Error handling
├── Retry logic
└── Monitoring/logging

Best Practices

For Effective Breakdown

Slice vertically — Full functionality, not layers

Keep tasks 1-3 days — Smaller is usually better

Include testing — Not a separate phase

Define done clearly — Testable acceptance criteria

Allow refinement — Details emerge during development

Anti-Patterns

AVOID THESE:
✗ Tasks that take weeks
✗ Horizontal slices (all DB, then all API)
✗ Testing as separate epic
✗ No acceptance criteria
✗ Breaking down too early (waste if priorities change)
✗ One person owns entire epic