Review Types

Review Types in ISTQB CTFL Static Testing

Understanding Review Types in Static Testing

Why Review Types Are Important

Review types are fundamental to the static testing process and are crucial for several reasons:

• Early Defect Detection: Reviews identify defects before dynamic testing begins, reducing costs significantly
• Quality Assurance: They ensure that deliverables meet specified standards and organizational guidelines
• Knowledge Sharing: Reviews facilitate communication and knowledge transfer among team members
• Risk Mitigation: Different review types target different risk areas within software development
• Compliance: In regulated industries, reviews provide documented evidence of quality assurance activities

What Are Review Types?

Review types are structured approaches to examining software work products such as requirements, design documents, code, and test cases. They are part of static testing and do not involve executing the software. The ISTQB CTFL framework recognizes several distinct review types, each with different levels of formality, structure, and participation.

The main review types are:

• Informal Review
• Walkthrough
• Technical Review
• Inspection

How Review Types Work

1. Informal Review

Definition: An unstructured review where a work product is checked by one or more people without following a formal process.

Characteristics:

• No formal process or documented procedure
• Minimal planning required
• No formal documentation of defects found
• Feedback is usually given informally
• Low cost and quick to perform

Process:

1. Developer shares work product with colleague(s)
2. Reviewer(s) examine the material casually
3. Issues are discussed informally
4. Developer makes corrections based on feedback

When to Use: Early in development, for low-risk items, or when time and resources are limited.

2. Walkthrough

Definition: A semi-formal review where the author walks through the work product with colleagues to gather feedback and detect defects.

Characteristics:

• Author-led process
• Informal, but structured approach
• Typically involves 3-6 participants
• Documented results, though not as rigidly as inspections
• Emphasis on learning and discovery
• No formal approval process

Process:

1. Author prepares the work product and invites reviewers
2. Author presents the material step-by-step
3. Reviewers ask questions and provide feedback
4. Issues and potential improvements are discussed
5. Issues are documented in a review report
6. Author addresses issues in revisions

When to Use: For design documents, algorithms, test cases, and requirements documents. Good for knowledge sharing and training.

3. Technical Review

Definition: A formal review where peers assess whether the work product conforms to standards, guidelines, and requirements.

Characteristics:

• Led by a qualified person (not the author)
• Formal process with clear roles (moderator, scribe, reviewers)
• Focused on technical quality and conformance
• Documentation of findings is required
• Typically involves 3-5 participants
• Approval is often required

Process:

1. Planning phase: Assigning roles and preparing materials
2. Kick-off: Overview of the work product and objectives
3. Individual preparation: Reviewers examine the material beforehand
4. Review meeting: Discussion of findings and issues
5. Documentation: Scribe records all defects and issues
6. Follow-up: Author resolves issues; moderator verifies corrections

When to Use: For critical work products, architectural designs, standards compliance checks, and deliverables that require formal approval.

4. Inspection

Definition: The most formal and rigorous type of review, with a well-defined process, specific roles, and detailed documentation. It aims to identify as many defects as possible.

Characteristics:

• Highly formalized and structured process
• Clearly defined roles with specific responsibilities
• Detailed preparation and planning phases
• Quantitative metrics collected
• Formal approval required before proceeding
• High cost but very effective at catching defects early
• Typically involves 3-6 participants

Key Roles in Inspection:

• Moderator: Leads the inspection, maintains schedule, manages the meeting
• Author: Presents the work product (though typically does not participate actively in defect identification)
• Scribe: Documents all defects and issues found
• Inspectors/Reviewers: Examine the work product and identify defects
• Manager: May attend but does not participate in defect identification (to reduce pressure on team members)

Inspection Process (Fagan's Model):

1. Planning: Define inspection scope, assign roles, schedule meeting
2. Overview/Kick-off: Author presents context and objectives
3. Preparation: Inspectors individually examine the work product using checklists
4. Inspection Meeting: Team discusses findings; defects are recorded
5. Rework: Author corrects identified defects
6. Follow-up: Moderator verifies corrections; re-inspection may be needed for major changes

When to Use: For critical code, complex designs, safety-critical systems, and high-risk components. Often used when quality is paramount and cost of defects is high.

Comparison of Review Types

How to Answer Exam Questions on Review Types

Question Type 1: Identifying the Correct Review Type

Example: "Which review type is characterized by the author leading a presentation of the work product to a small group of reviewers?"

Approach:

• Identify key characteristics mentioned in the question
• Match those characteristics to the review type definitions
• Look for differentiating factors like who leads (author vs. moderator), formality level, and documentation
• Answer: Walkthrough (author-led, semi-formal)

Question Type 2: Selecting Appropriate Review Type for a Scenario

Example: "A safety-critical component needs thorough defect detection with formal documentation and approval. Which review type is most appropriate?"

Approach:

• Consider the risk level and criticality of the work product
• Evaluate resource availability and time constraints
• Determine if formal approval is required
• Match requirements to review type characteristics
• Answer: Inspection (highest formality, best for critical systems)

Question Type 3: Matching Characteristics to Review Types

Example: "Which of the following is NOT a characteristic of an informal review?"

Approach:

• Review characteristics of each type
• Eliminate options that ARE characteristics of informal reviews
• Select the option that contradicts informal review definition
• Correct answers typically mention: formal documentation, approval processes, defined roles, or structured procedures

Question Type 4: Understanding Review Roles

Example: "In an inspection, who is responsible for recording all defects found during the inspection meeting?"

Approach:

• Recall the specific roles defined in inspection (moderator, author, scribe, inspector, manager)
• Match the responsibility to the correct role
• Answer: Scribe

Question Type 5: Process Steps and Sequence

Example: "In Fagan's inspection process, what is the correct sequence of phases?"

Approach:

• Remember the Fagan inspection sequence: Planning → Overview → Preparation → Inspection Meeting → Rework → Follow-up
• Eliminate options with incorrect sequences
• Select the option matching the standard process

Exam Tips: Answering Questions on Review Types

1. Memorize Key Differentiators

• Informal: Unstructured, no documentation, author doesn't lead
• Walkthrough: Author-led, semi-formal, some documentation
• Technical Review: Peer-led (not author), formal, approval required
• Inspection: Moderator-led, most formal, detailed metrics, best defect detection

2. Watch for Keywords in Questions

• "Author presents" → Walkthrough
• "Highly formalized" or "critical system" → Inspection
• "Quick feedback" or "low-cost" → Informal
• "Peers assess conformance" or "not the author leads" → Technical Review
• "Moderator," "scribe," "roles" → Inspection

3. Understand the Formality Spectrum

Always remember: Informal < Walkthrough < Technical Review < Inspection

If a question asks for the "most formal" review type, the answer is Inspection. If it asks for the "least formal," the answer is Informal Review.

4. Know the Purpose of Each Type

• Informal: Quick feedback and learning
• Walkthrough: Knowledge sharing and collaborative learning
• Technical Review: Conformance to standards and technical quality
• Inspection: Maximum defect detection and early quality assurance

5. Master Inspection-Specific Knowledge

Since inspection is the most formal, it appears frequently in exams:

• Know the six phases of Fagan's model
• Understand each inspection role and responsibilities
• Remember that metrics are collected in inspections
• Know that re-inspection may be needed for major changes

6. Pay Attention to Role Descriptions

Exam questions often describe a specific role without naming it. Match the description:

• "Records all findings" → Scribe
• "Leads and manages the process" → Moderator
• "Presents the work product" → Author
• "Identifies defects independently" → Inspector/Reviewer

7. Understand Cost vs. Benefit

High-cost reviews (inspection) are justified for:

• Safety-critical systems
• High-complexity components
• Early lifecycle phases where defect fixing is cheapest
• Products with high cost of failure

8. Remember Context Clues

• Early development, training context → Walkthrough
• Standards compliance checking → Technical Review
• Code review for quality gates → Could be any type depending on rigor needed
• Safety-critical software → Inspection

9. Don't Confuse Walkthrough and Technical Review

These are commonly confused. The key difference:

• Walkthrough: Author leads, learning-focused, semi-formal
• Technical Review: Moderator (not author) leads, conformance-focused, formal

10. Practice with Scenario-Based Questions

Most exam questions present scenarios. Always ask yourself:

1. What is the risk level? (High = Inspection or Technical Review)
2. Who leads? (Author = Walkthrough; Moderator = Technical Review or Inspection)
3. How much formality is needed? (Safety/compliance = Inspection)
4. What is the main goal? (Learning = Walkthrough; Quality assurance = Technical Review or Inspection)

11. Remember Key ISTQB Definitions

Use the exact terminology:

• Informal review is "unstructured"
• Walkthrough is "semi-formal"
• Technical review focuses on "conformance to standards"
• Inspection is the "most rigorous form of review" with "metrics-driven" approach

12. When Unsure, Use Process Elimination

• If the answer mentions "author leads," eliminate technical review and inspection
• If it mentions "metrics," it's likely inspection
• If it mentions "quick and informal," it's informal review
• If it mentions "peer assessment" and "moderator," it's technical review

13. Understanding Defect Detection Rates

Exams may ask which review type catches the most defects:

• Inspection > Technical Review > Walkthrough > Informal

Inspection's detailed process, preparation phase, and multiple reviewers make it the most effective.

14. Be Clear on Documentation Requirements

• Informal: No formal records required
• Walkthrough: Review report prepared, but not as detailed
• Technical Review: Formal record of findings, approval documentation
• Inspection: Detailed defect logs, metrics, inspection report

15. Final Quick Reference for Exam Day

Summary

Review types are a critical component of static testing in the ISTQB CTFL curriculum. Success on exam questions about review types depends on:

• Understanding the four main review types and their defining characteristics
• Recognizing keywords and context clues in questions
• Knowing the formality spectrum and when each type is appropriate
• Mastering inspection-specific details (roles, phases, metrics)
• Using process elimination when unsure of the answer

With consistent practice and understanding of these fundamentals, you will be well-prepared to answer any question about review types on the ISTQB CTFL exam.