HKSM

What-if scenario analysis is a technique to explore how changes in assumptions, constraints, or events could affect project objectives. The team models alternative scenarios to compare outcomes and plan responses.

Definition

Refer to the definition above.

Key Points

• Explores how alternative assumptions or events impact schedule, cost, scope, quality, and resources.
• Supports proactive risk management, contingency planning, and decision making.
• Can be qualitative (logic-based) or quantitative (e.g., scheduling tools, simulations).
• Quality of results depends on the accuracy of data, model structure, and stated assumptions.
• Performed iteratively during planning and when major changes or risks emerge.
• Outputs guide reserves, response strategies, and communication with stakeholders.

Purpose of Analysis

• Anticipate how potential changes could affect project outcomes.
• Identify vulnerabilities and areas needing contingency plans or reserves.
• Compare alternative courses of action to select the most resilient plan.
• Support informed go/no-go and risk response decisions.

Method Steps

• Define the question: clarify the decision or risk you need to explore.
• Set assumptions and variables: identify what may change (e.g., durations, costs, resource availability, external events).
• Build or reference a model: use the current schedule, cost model, or simple spreadsheet logic.
• Create scenarios: best case, worst case, most likely, and targeted scenarios for specific risks.
• Analyze impacts: evaluate effects on critical path, milestones, cost baseline, resources, and benefits.
• Compare results: identify thresholds, tipping points, and the most sensitive variables.
• Recommend actions: propose responses, reserves, or plan adjustments and record decisions.

Inputs Needed

• Baseline plans and models (schedule, cost, scope, quality criteria).
• Assumptions and constraints from the project charter and plans.
• Risk register entries, including threats, opportunities, and triggers.
• Resource calendars, capacity, and availability data.
• Historical data, expert judgment, and organizational process assets.
• External factors such as market conditions or regulatory timelines.

Outputs Produced

• Scenario results highlighting impacts on time, cost, scope, and quality.
• Sensitivity insights showing which variables drive outcomes most.
• Recommended risk responses, reserves, and contingency or fallback plans.
• Updates to the schedule, cost baseline, and risk register.
• Decision log entries and communication materials for stakeholders.

Interpretation Tips

• Focus on trends and relative changes, not just single-point estimates.
• Assess both impact and likelihood to prioritize responses.
• State assumptions clearly so results are traceable and reusable.
• Validate the model with peers or experts to reduce bias and errors.
• Present ranges or scenarios with confidence levels where possible.
• Link scenarios to triggers and decision checkpoints.

Example

The team models a scenario where a critical component delivery is delayed by two weeks. The schedule tool shows the critical path shifts, milestones slip by nine days, and additional overtime cost is required. The team adds a supplier expediting option as a contingency and updates the risk register with triggers and reserves.

Pitfalls

• Overcomplicating models so results are hard to explain or use.
• Changing one variable at a time and missing interactions among factors.
• Using outdated data or unstated assumptions that undermine credibility.
• Confirmation bias leading to scenarios that fit preferred outcomes.
• Confusing scenarios with forecasts by implying probability where none is assessed.
• Failing to translate insights into concrete plans and decision criteria.

PMP Example Question

During schedule planning, the team is concerned that a regulatory approval might be delayed. Which action best applies what-if scenario analysis?

1. Record the potential delay as an issue and continue with the baseline plan.
2. Model a scenario where the approval slips by three weeks and assess effects on the critical path and resource plan.
3. Request immediate additional budget to cover any potential delay.
4. Freeze scope to avoid further changes to the schedule.

Correct Answer: B — Model a scenario where the approval slips by three weeks and assess effects on the critical path and resource plan.

Explanation: What-if scenario analysis evaluates outcomes by changing assumptions or events and analyzing impacts to plan appropriate responses.