Requirements Quality

Requirements quality assessment, INVEST criteria validation, and refinement patterns.

When to Use This Skill

Keywords: INVEST, requirements quality, clarity, ambiguity, completeness, testable, estimable, refinement, MoSCoW, prioritization, acceptance criteria, requirement validation, quality assessment

Use this skill when:

Evaluating requirements against INVEST criteria
Improving requirement clarity and precision
Detecting and resolving ambiguity
Ensuring requirements are complete
Applying MoSCoW prioritization
Refining requirements iteratively
Validating acceptance criteria quality

INVEST Criteria Overview

The INVEST acronym defines six quality criteria for well-formed requirements:

| Criterion | Question | Red Flag | | --- | --- | --- | | Independent | Can this be implemented alone? | "Requires X to be done first" | | Negotiable | Is there room for discussion? | Over-specified implementation | | Valuable | Does it deliver user value? | Technical-only benefit | | Estimable | Can effort be estimated? | Vague or unbounded scope | | Small | Can it be done in one iteration? | Multi-sprint scope | | Testable | Can we verify it's done? | Missing acceptance criteria |

Quick Quality Assessment

Rapid INVEST Check

For each requirement, score 0-2 on each criterion:

| Score | Meaning | | --- | --- | | 0 | Does not meet criterion | | 1 | Partially meets criterion | | 2 | Fully meets criterion |

Interpretation:

10-12: High quality, ready for implementation
7-9: Acceptable, minor improvements needed
4-6: Needs work, significant refinement required
0-3: Not ready, major rewrite needed

Common Quality Issues

| Issue | Symptom | Fix | | --- | --- | --- | | Too vague | "Make it user-friendly" | Add measurable criteria | | Too large | Multi-week estimate | Split into smaller requirements | | Untestable | No clear success condition | Add acceptance criteria | | Dependent | "After X is complete" | Decouple or combine | | Technical | "Refactor database" | Reframe as user value | | Over-specified | Implementation details | Focus on what, not how |

MoSCoW Prioritization

Priority Levels

| Priority | Meaning | Guidance | | --- | --- | --- | | Must | Critical for release | Without this, release fails | | Should | Important but not critical | High value, schedule permitting | | Could | Nice to have | Include if time allows | | Won't | Out of scope (this time) | Explicitly deferred |

Prioritization Questions

What happens if we don't include this?
Is there a workaround without this?
How many users are affected?
What's the business impact?
Are there dependencies on this?

Clarity Enhancement Patterns

Ambiguity Detection

Ambiguous Words to Avoid:

| Word | Problem | Better Alternative | | --- | --- | --- | | "should" | Unclear obligation | "SHALL" (mandatory) or "MAY" (optional) | | "quickly" | Subjective timing | "within 200ms" | | "user-friendly" | Subjective quality | Specific usability criteria | | "etc." | Incomplete list | Exhaustive enumeration | | "appropriate" | Vague standard | Specific criteria | | "some" | Undefined quantity | Explicit count or range | | "easy" | Subjective difficulty | Measurable steps |

Clarity Checklist

[ ] Uses specific, measurable terms
[ ] Avoids ambiguous words
[ ] Defines all acronyms on first use
[ ] Includes units for all quantities
[ ] Specifies actors clearly
[ ] Defines success conditions

Acceptance Criteria Quality

Good Acceptance Criteria

Each acceptance criterion should be:

Atomic: Tests one thing
Precise: Clear pass/fail
Complete: Covers the requirement
Independent: Tests can run in any order

Given/When/Then Format

Given [precondition]
When [action]
Then [expected outcome]

Quality Check:

[ ] Given establishes clear context
[ ] When describes specific trigger
[ ] Then defines observable outcome
[ ] Covers happy path and error cases
[ ] Each AC is independently testable

Refinement Workflow

Standard Refinement Process

1. Draft Requirement
   ↓
2. INVEST Assessment (score each criterion)
   ↓
3. Identify Issues (low-scoring criteria)
   ↓
4. Apply Fixes (use patterns below)
   ↓
5. Re-assess (verify improvements)
   ↓
6. Add Acceptance Criteria
   ↓
7. Final Validation

Iteration Patterns

When Independent fails:

Extract dependencies into separate requirements
Or combine tightly coupled requirements

When Negotiable fails:

Remove implementation details
Focus on outcomes, not methods

When Valuable fails:

Reframe in user terms
Connect to business goal

When Estimable fails:

Add constraints and boundaries
Define scope limits

When Small fails:

Split by user type
Split by scenario
Split by CRUD operation

When Testable fails:

Add acceptance criteria
Define success metrics

Completeness Validation

Requirement Completeness

A complete requirement includes:

| Element | Description | Required? | | --- | --- | --- | | ID | Unique identifier | Yes | | Title | Brief descriptive title | Yes | | Description | Full requirement text | Yes | | Priority | MoSCoW level | Yes | | Acceptance Criteria | Testable conditions | Yes | | Dependencies | Related requirements | If any | | Assumptions | Underlying assumptions | If any | | Constraints | Limitations | If any |

Specification Completeness

A complete specification includes:

[ ] All functional requirements identified
[ ] Non-functional requirements included
[ ] Edge cases considered
[ ] Error handling specified
[ ] Security requirements addressed
[ ] Performance criteria defined
[ ] Accessibility requirements included
[ ] All requirements prioritized
[ ] Dependencies mapped
[ ] Assumptions documented

Quick Commands

| Action | Command | | --- | --- | | Assess requirement quality | /spec:validate <path> | | Refine requirements | /spec:refine <path> | | Audit specification | /spec:audit <path> |

Related Skills

ears-authoring - EARS pattern authoring
gherkin-authoring - Given/When/Then criteria
canonical-spec-format - Canonical specification structure
spec-management - Specification workflow hub

References

Detailed Documentation:

INVEST Criteria - INVEST principles with examples
Refinement Patterns - Refinement techniques
Completeness Checklist - Validation checklist

Last Updated: 2025-12-24

Version History

v1.0.0 (2025-12-26): Initial release