CTFL-AcT Exam Dumps : ISTQB Certified Tester - Acceptance Testing (CT-AcT)

ISO/IEC 25010 defines two key quality models:

Product Quality Model (e.g., Usability, Security, Portability)

Quality in Use Model — which includes characteristics of the user’s experience when interacting with the product in a real-world context.

The four main characteristics of the Quality in Use model are:

Effectiveness

Efficiency

Satisfaction

Freedom from risk

Option A — Efficiency is one of the key Quality in Use characteristics, as it refers to the resources used to achieve goals with accuracy and completeness.

Other options:

B (Usability), C (Compatibility), and D (Portability) are characteristics of the Product Quality Model, not of Quality in Use.

Therefore, the correct answer, as per ISO 25010:2011, is:

Answer: A. Efficiency

UX task analysis focuses on understanding how users perform their tasks in real-world contexts. It captures not only the sequence of actions but also the surrounding environment — including physical conditions (light, noise), devices used, interruptions, and constraints. These external or environmental conditions become vital inputs to UX design decisions, helping teams adapt interfaces and workflows to user realities.

Option C is correct because it emphasizes this key aspect of UX task analysis: capturing external conditions that influence usability and system interaction.

Other options:

A focuses on user profiling, not task analysis.

B refers to business process modeling, which is more strategic and less user-context specific.

D refers to benchmarking or inspiration analysis — useful for design ideation but not task analysis.

Answer: C. External conditions are considered as input for subsequent design steps.

Clear, complete, and testable requirements or user stories are critical for effective acceptance testing. Ambiguities or vague statements lead to differing interpretations by stakeholders, developers, and testers. This often results in software that doesn’t meet user expectations or in tests that fail to verify business needs correctly.

Option B is correct because it highlights the importance of precise requirements in both implementation and testing phases. Ambiguities can result in incorrect behavior, untestable features, or test cases that don’t align with business goals.

Other options:

A is risky — while testers may explore assumptions during exploratory testing, relying on assumptions rather than clarification increases risk.

C is incorrect — the INVEST mnemonic helps write better user stories, but it doesn’t replace review or validation processes.

D is false — Agile still values requirements engineering; it’s more collaborative and incremental, with the product owner playing a key role, not diminishing its importance.

Answer: B. Vague or ambiguous requirements may lead to misunderstandings both during implementation and testing