SWE3411 Midterm I

Requirements engineering

Eliciting, analyzing, specifying, validating, and managing system needs.

Why are requirements important?

They define scope and guide design, testing, cost, and stakeholder agreement.

Business vs. user vs. functional requirements

Business = why/value; user = goals/tasks; functional = system behavior.

Functional requirement (FR) vs. nonfunctional requirement (NFR)

FR = what the system does; NFR = how well it performs or constraints it meets.

Product vs. project requirements

Product = system capabilities/qualities; project = work and delivery constraints.

Stakeholder vs. customer vs. user

Stakeholder = affected/influential; customer = requests/pays; user = operates.

Expectation gap

Difference between stakeholder expectations and planned delivery; reduce it by clarifying and validating scope.

Stakeholder analysis

Identify groups, their goals, influence, conflicts, and how they will participate.

Business objective vs. success metric

Objective = desired outcome; metric = measurable target proving success.

Vision vs. product scope

Vision = purpose and value; scope = included/excluded capabilities and boundaries.

Assumption vs. risk vs. constraint

Assumption = unverified belief; risk = possible problem; constraint = required limitation.

User class vs. persona

User class = people with similar goals/access; persona = evidence-based example of one class.

Product champion and voice of the user

Champion represents a user class; verify their claims with actual users, not just one opinion.

Requirements elicitation

Discover needs through interviews, observation, workshops, documents, surveys, and prototypes.

What belongs in an elicitation plan?

Who to consult, what to learn, techniques, questions, timing, and outputs.

Open vs. closed vs. leading interview questions

Open explores; closed confirms facts; leading biases an answer and should be avoided.

Why ask follow-up and 'what if' questions?

To uncover examples, assumptions, edge cases, errors, and missing requirements.

Observation vs. interviews

Observation shows actual behavior/workarounds; interviews explain goals and reasoning.

Evidence vs. assumption

Evidence is supported by a source or observation; an assumption needs validation.

How do you validate elicitation findings?

Summarize them to stakeholders and confirm accuracy, omissions, and disagreements.

User story format

As a [user role], I want [capability], so that [benefit].

Acceptance criteria

Testable conditions that determine whether a story or requirement is satisfied.

User story vs. use case

Story briefly states a goal and value; use case details actor-system interactions.

Actor and primary actor

Actor = external role/system interacting with product; primary actor pursues the main goal.

Use case trigger vs. precondition vs. postcondition

Trigger starts it; precondition must already hold; postcondition describes final state.

Normal vs. alternate vs. exception flow

Normal = main success path; alternate = valid variation; exception = error/failure path.

Business rule vs. functional requirement

Rule = governing policy or constraint; FR = system behavior enforcing or supporting it.

SRS (Software Requirements Specification)

Organized, agreed record of FRs, NFRs, interfaces, data needs, and constraints.

What makes a requirement easy to reference?

A unique stable ID, clear label, source, and links to related tests or use cases.

Requirements traceability

Links business goals to requirements, design, and tests to track coverage and change impact.

Requirements baseline vs. scope creep

Baseline = approved requirements version; scope creep = uncontrolled expansion beyond it.

Characteristics of excellent requirements

Correct, complete, necessary, feasible, clear, consistent, prioritized, verifiable, modifiable, traceable.

Unambiguous vs. verifiable requirement

Unambiguous = one reasonable interpretation; verifiable = can objectively pass/fail.

Atomic requirement

States one independently testable obligation; avoid combining unrelated behaviors.

Why is 'The system shall be fast' a weak requirement?

'Fast' is subjective; specify a measurable threshold and conditions, such as 2 s at 100 users.

How should a functional requirement be phrased?

Use a clear trigger/condition, system action, and observable result; e.g., 'When X, the system shall Y.'

Work context diagram

Shows the system boundary, external actors/systems, and information crossing that boundary.

Data requirements vs. data dictionary

Data requirements say what data is needed; a dictionary defines fields, types, meanings, and rules.

External interface requirements

Define exchanges with users, hardware, software, or networks, including formats and expected behavior.

Common software quality attributes

Performance, reliability, availability, usability, accessibility, security, privacy, maintainability.

Fit criterion

Objective threshold/test for an NFR, including a metric and operating conditions.

Reliability vs. availability

Reliability = operates without failure; availability = proportion of time usable.

Requirements prioritization and MoSCoW

Rank by value, risk, urgency, cost; Must, Should, Could, Won't (for now).

Low- vs. high-fidelity prototype

Low = quick sketch/flow; high = realistic detailed UI/behavior.

How do prototypes reduce requirements risk?

Expose misunderstandings and usability problems early; a prototype is not an approved spec.

Requirements validation vs. verification

Validation = are these the right needs? Verification = are requirements specified correctly?

Requirements review checklist

Check omissions, ambiguity, contradictions, feasibility, testability, scenarios, and NFR metrics.

Review finding vs. approved change

Finding flags a defect; change requires a decision, revision, trace update, and revalidation.

Defect severity vs. priority

Severity = impact if unfixed; priority = urgency of fixing it.

Responsible AI in requirements work

Use AI to critique, roleplay, probe, or check clarity; verify outputs with real evidence and stakeholders.