Independence of Testing
1. Introduction
The independence of testing is an ISTQB concept that explains why having someone other than the author test the work can improve defect detection.
This question checks whether you understand both:
- the main benefit of independent testing
- the main drawback (possible isolation and communication issues)
테스트 독립성(Independence of Testing)은 “작성자(개발자) 외의 사람이 테스트하면 결함을 더 잘 찾을 수 있다”는 개념입니다. 이 문제는 독립성의 장점과 동시에 발생할 수 있는 단점(고립, 협업/소통 문제)까지 이해하는지 확인합니다.
2. Key Concept: Why Independence Helps (and What It Can Break)
Independence helps because testers may:
- have different backgrounds and viewpoints
- avoid the author’s cognitive bias
- focus on user and risk perspectives
But independence can also create risks:
- testers become isolated from the dev team
- communication and collaboration weaken
- an “us vs. them” (adversarial) relationship forms
독립성의 장점은 테스터가 개발자와 다른 시각을 가지며, 작성자 편향(인지 편향)을 줄이고 사용자/리스크 관점에서 결함을 찾기 쉽기 때문입니다. 반대로 팀에서 고립되면 소통이 약해지고 “대립 관계”가 생길 수 있다는 점이 대표 단점입니다.
3. Practice Question
❓ Question
Which of the following statements about the independence of testing is CORRECT?
- a) Independent testers will find defects due to their different technical perspective from developers, but their independence may lead to an adversarial relationship with the developers
- b) Developers’ familiarity with their own code means they only find a few defects in it, however their shared software background with testers means these defects would also be found by the testers
- c) Independent testing requires testers who are outside the developer’s team and ideally from outside the organization, however these testers find it difficult to understand the application domain
- d) Testers from outside the developer’s team are more independent than testers from within the team, but the testers from within the team are more likely to be blamed for delays in product release
✅ Correct Answer: a)
4. Explanation (EN / KR)
✔ a) Different viewpoint + possible adversarial relationship — Correct
The primary benefit of independent testing is that testers often identify different types of failures and defects than developers, due to different backgrounds, viewpoints, and reduced cognitive bias.
The main disadvantage is that strong independence can isolate testers, leading to:
- communication problems
- reduced collaboration
- an adversarial relationship (testers blamed for delays/bottlenecks)
독립성의 가장 큰 장점은 개발자와 다른 관점/배경 덕분에 테스터가 다른 종류의 결함을 더 잘 발견할 수 있다는 점입니다(인지 편향 감소 포함). 하지만 독립성이 강해지면 테스터가 팀에서 고립되어 협업이 약해지고, 출시 지연의 “원인”처럼 비난받으며 대립 구조가 생길 수 있습니다.
❌ b) Developers only find a few defects + shared background — Incorrect
Developers’ familiarity with their code does not mean they only find a few defects. It often helps them find many defects efficiently.
Also, independence benefits are often explained by different backgrounds between developers and testers, not a shared one.
개발자가 자기 코드를 잘 안다고 해서 결함을 “조금만” 찾는 것은 아닙니다. 오히려 익숙함 덕분에 많은 결함을 효율적으로 찾을 수도 있습니다. 또한 독립성의 장점은 개발자-테스터의 배경 차이에서 나오기 때문에 ‘공유된 배경’이라는 설명도 부적절합니다.
❌ c) Independence requires outsiders + domain understanding issue — Incorrect
Independence has multiple levels (from the author to external testers). Testers do not need to be outside the organization to be “independent.”
Domain knowledge varies by project and person—it is not determined by independence level.
독립성은 한 가지 형태가 아니라 여러 수준이 있습니다(작성자 테스트부터 외부 조직까지). 독립 테스트가 반드시 외부 조직이어야 하는 것은 아닙니다. 또한 도메인 이해도는 개인/프로젝트에 따라 달라지며 독립성 수준으로 결정되지 않습니다.
❌ d) Who gets blamed for delays — Incorrect
It is reasonable that testers outside the team are more independent than those inside, but it is more plausible that outsiders become isolated and are blamed for delays, not the testers inside the team.
팀 밖 테스터가 더 독립적인 것은 맞을 수 있지만, 지연의 책임을 더 많이 뒤집어쓸 가능성은 오히려 팀 밖(고립되기 쉬운) 테스터 쪽이 큽니다. 따라서 d)의 주장 방향이 ISTQB 관점과 맞지 않습니다.
5. Summary Table
| Option | Result | Key Idea | 한글 요약 |
|---|---|---|---|
| a | ✔ Correct | Different viewpoint + possible adversarial relationship | 다른 관점(장점) + 고립/대립(단점) |
| b | ✖ | Wrong assumptions about developer detection & background | 개발자 결함 탐지/배경 설명 오류 |
| c | ✖ | Independence has levels; domain knowledge not determined by it | 독립성은 수준 다양, 도메인 이해와 무관 |
| d | ✖ | Blame is more likely for isolated outsiders | 지연 비난은 고립되는 외부 쪽 가능성 |
6. Final Takeaway
For ISTQB exams, remember:
Independence improves defect detection, but too much independence can reduce collaboration.
시험에서는 이 한 줄로 정리하면 됩니다.
테스트 독립성은 결함 탐지에 유리하지만, 지나치면 협업/소통을 해칠 수 있다.
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