Expert Judgment Estimation

Overview

Expert Judgment Estimation is a qualitative estimation technique that relies on the input, knowledge, and experience of individuals or groups with specialized expertise in a particular area. This method is valuable when historical data is limited or when dealing with unique or complex projects.

When to Use Expert Judgment

• Limited or no historical data available
• Unique or first-of-its-kind projects
• Rapidly changing technologies or methods
• Complex projects requiring specialized knowledge
• Validating estimates from other techniques
• Early project phases with high uncertainty
• Identifying risks and assumptions

Types of Experts

• Internal Experts: Team members with relevant experience
• External Consultants: Industry specialists or advisors
• Vendors: Suppliers with product-specific knowledge
• Subject Matter Experts (SMEs): Specialists in specific domains
• Experienced Project Managers: Those who have managed similar projects

Methods for Gathering Expert Judgment

Individual Consultation

• One-on-one interviews with experts
• Detailed discussion of assumptions and constraints
• Personalized estimates based on specific context

Delphi Technique

• Anonymous rounds of expert estimates
• Facilitator compiles and shares results
• Experts revise estimates based on group feedback
• Continues until consensus is reached

Group Brainstorming

• Collaborative session with multiple experts
• Open discussion of estimates and rationale
• Team reaches consensus through dialogue

Wideband Delphi

• Combination of individual and group techniques
• Experts review requirements independently
• Group meeting to discuss and refine estimates
• Anonymous re-estimation after discussion

Best Practices

• Select Appropriate Experts: Choose individuals with relevant, recent experience
• Provide Context: Share complete project information and constraints
• Avoid Bias: Use anonymous techniques when possible to prevent groupthink
• Document Assumptions: Record the reasoning behind estimates
• Use Multiple Experts: Gather diverse perspectives to reduce individual bias
• Combine Methods: Use expert judgment alongside data-driven techniques
• Review Regularly: Update estimates as experts gain project-specific knowledge
• Consider Confidence Levels: Ask experts to rate their certainty

Advantages

• Leverages valuable experience and insights
• Useful when data is unavailable or inadequate
• Can account for unique project factors
• Relatively quick to implement
• Helps identify risks and issues early
• Builds team buy-in and commitment

Disadvantages

• Subjective and potentially biased
• Quality depends on expert selection
• Can be influenced by organizational politics
• May lack transparency in reasoning
• Different experts may provide conflicting estimates
• Overconfidence in expert opinions can lead to errors

Improving Accuracy

• Cross-validate with multiple experts
• Combine with quantitative methods when possible
• Ask experts to explain their reasoning
• Review past estimates vs. actual results to calibrate
• Use structured techniques like Delphi to reduce bias
• Document lessons learned for future reference

Common Applications

• New technology implementations
• Custom software development
• Organizational change initiatives
• Research and development projects
• First-time vendor relationships
• Regulatory compliance projects
• Strategic planning initiatives

Hybrid Approaches

Often combined with:

• Analogous estimating for comparison
• Parametric estimating using expert-provided parameters
• Bottom-up estimating with expert input on tasks
• Three-point estimation using expert optimistic/pessimistic scenarios