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Software Architecture Guide

Agile Enterprise Backlog Model

Explanation

Section titled “Explanation”

The model describes how requirement work items relate when agile teams work at large scale. Each level sits below the one above it.

The levels

  • Themes sit at the top. They live much longer than epics. A set of themes may stay largely unchanged for a year or more.
  • Epics are the highest-level expression of a customer need. They are held in an epic backlog. (See the article Epic.)
  • Features and stories come below epics. (See User Story.)
  • Tasks sit below stories. Each team member estimates the tasks needed to achieve a story.

Business and enabler epics

SAFe is a later framework. It separates business epics from enabler epics. Enabler epics improve the architectural runway. That runway supports future business or technical needs.

SAFe also manages epics at the portfolio level. It uses a Kanban system for this, which makes the epics easier to see and track.

Verification

Tests show when work is done.

  • A story is not done until it passes an acceptance test. (See Acceptance Criterion.)
  • Features usually need one or more functional acceptance tests too. These check that the feature meets the user’s needs.
  • A system is compliant when it passes system validation tests. These tests verify the nonfunctional requirements.

Example

Section titled “Example”

A company keeps a long-lived theme: “make ordering easier for customers”. One epic under it is “support mobile payments”. The epic holds features such as “save a card”. Each feature holds stories, and each story holds tasks that team members estimate. A story is done when its acceptance test passes. The system as a whole is compliant when its system validation tests pass.

Trade-offs

Section titled “Trade-offs”

The facts here describe the levels and the tests. They do not cover costs or limits of the model. Teams should check how the model fits their own scale before adopting all the levels.

Backlog levels and the tests that verify them

Diagram source 
flowchart TD
  T[Theme] --> E[Epic]
  E --> F[Feature]
  F --> S[Story]
  S --> K[Task]
  AT[Acceptance tests] -.verify.-> S
  AT -.verify.-> F
  SV[System validation tests] -.verify.-> NFR[Nonfunctional requirements]

Checks

Section titled “Checks”
  • Stories are marked done only when an acceptance test passes.
  • Features have one or more functional acceptance tests.
  • System validation tests exist to verify the nonfunctional requirements.
  • Architecture work is shown as enabler epics, separate from business epics.
Section titled “Related”

Sources

Section titled “Sources”