What is Expert Judgment in Empirical Estimation Models?
Expert judgment is a key component of empirical estimation models, where the estimation of project parameters (such as cost, duration, and effort) is based on the experience and expertise of individuals or groups who have worked on similar projects. The judgment and insights provided by these experts are used to forecast project outcomes and make informed decisions about the project’s planning and execution.
🔹 Key Objective: Leverage the knowledge and experience of experts to estimate project parameters and guide project planning.
Importance of Expert Judgment
✔ Incorporates Experience: Leverages real-world knowledge from professionals who have worked on similar projects.
✔ Quick Estimation: Provides relatively fast estimates when historical data may not be available or is limited.
✔ Subject Matter Expertise: Expert judgment taps into specialized knowledge that data-driven models may not always account for.
✔ Risk Management: Experts can identify hidden risks or complexities that may not be immediately obvious in data or theoretical models.
✔ Adaptable: Suitable for novel, uncertain, or complex projects where historical data or similar projects may be sparse.
When is Expert Judgment Used in Project Estimation?
1. Lack of Historical Data
When previous project data is insufficient or unavailable, expert judgment provides an informed estimate based on similar projects or experiences in the same domain.
📌 Example:
If your project involves new technology or a unique product, experts can provide estimates based on their prior exposure to related work.
2. Novel or Complex Projects
In cases where a project is highly complex or unprecedented, experts use their experience to estimate elements of the project that cannot be easily quantified using traditional estimation techniques.
📌 Example:
Developing a cutting-edge AI system or designing a unique software architecture requires experts to make educated guesses on time, cost, and resources.
3. Short Timeframe for Estimation
When there is a need for quick estimations (e.g., during the project initiation phase or early planning stages), expert judgment can provide fast insights, helping to move the project forward.
📌 Example:
In a startup environment, project timelines and budgets need to be quickly estimated to secure investor funding. Experts in the field can make quick yet informed projections.
How Expert Judgment Works in Empirical Estimation
Expert judgment is typically used in the following ways:
1. Selecting Experts
Identify individuals or teams with relevant expertise and experience in the project domain. These could be:
- Project Managers with prior experience on similar projects.
- Subject Matter Experts (SMEs) who have deep knowledge in specific areas (e.g., developers, architects, engineers).
- Consultants or industry experts with insights into best practices and project benchmarks.
2. Gathering Insights
Experts are asked to provide estimates or assessments based on their knowledge, often considering:
- Past experiences with similar projects.
- Industry benchmarks.
- Known risks and uncertainties.
- Challenges faced in previous projects.
3. Group Discussions or Delphi Technique
Sometimes, estimates are derived from a group of experts rather than an individual. This process helps reduce biases and ensures diverse perspectives are considered. One well-known method is the Delphi Technique:
- Experts are asked to make independent estimates.
- Results are shared, and feedback is provided to experts.
- Experts revise their estimates in the next round, which continues until consensus is reached.
4. Synthesizing Expert Opinions
Once insights are gathered from experts, their estimates are aggregated to form a final estimate. This may involve considering the average, the range (optimistic, pessimistic), or applying weighting depending on expert confidence and relevance to the project.
Expert Judgment vs. Other Estimation Models
| Aspect | Expert Judgment | Analogous Estimating | Parametric Estimating |
|---|---|---|---|
| Basis for Estimation | Based on the experience and knowledge of experts | Based on historical data from similar projects | Based on mathematical formulas and project variables |
| Speed | Quick and flexible, but requires expert availability | Fast if historical data is available | Requires data and can be complex |
| Accuracy | Can be highly accurate if the right experts are selected | Depends on similarity to past projects | More precise when data is reliable and accurate |
| Applicability | Best for new, complex, or uncertain projects | Best for projects similar to past ones | Works best with measurable and consistent variables |
| Common Use Cases | Highly uncertain, unique, or innovative projects | Routine, well-understood projects | Projects with clear and repeatable patterns |
How to Use Expert Judgment Effectively
Step 1: Identify the Right Experts
Choose experts with relevant experience and knowledge related to your project. Consider:
- Previous experience in similar projects.
- Deep knowledge of specific technologies or processes.
- Experience in managing or delivering complex projects.
📌 Example:
For a new e-commerce platform, a UI/UX expert, full-stack developer, and e-commerce consultant might be suitable experts for judgment.
Step 2: Establish Clear Objectives
Clearly define what you need the experts to estimate (e.g., cost, effort, resources, risks) and ensure their judgment is aligned with the project goals.
Step 3: Conduct Individual or Group Discussions
Engage with the experts either through individual interviews or group discussions. You can use techniques like:
- One-on-One Interviews for focused insights.
- Delphi Technique for consensus building among multiple experts.
- Brainstorming Sessions to generate multiple estimation scenarios.
Step 4: Combine Expert Opinions
After gathering insights, combine the estimates from different experts. This can be done through:
- Averaging: Taking the average of all expert estimates.
- Weighting: Giving more weight to experts with more relevant experience or track record.
- Range Estimates: Using a range (optimistic to pessimistic) for estimates if there is significant uncertainty.
Step 5: Validate and Adjust Estimates
Once the initial estimate is formed, validate it by comparing with any available historical data or other estimation models (e.g., analogous or parametric). Adjust based on feedback from stakeholders.
Step 6: Continuous Refinement
As the project progresses and more information becomes available, refine the estimates using updated expert judgment, along with actual performance data.
Example of Using Expert Judgment for Estimation
For a Software Development Project:
- Project: Develop a new mobile app.
- Objective: Estimate the effort required for backend development.
- Expert Selection: Choose 3 senior software engineers who have worked on similar mobile apps in the past.
- Estimation Process:
- Each expert provides an estimate for the backend development effort (in hours).
- Expert 1: 500 hours
- Expert 2: 600 hours
- Expert 3: 550 hours
- Combining Estimates: Average estimate = (500 + 600 + 550) / 3 = 550 hours.
- Validation: Compare with previous projects (if available). Adjust if necessary.
Benefits of Using Expert Judgment
✔ Faster Estimation: Especially useful in early project phases when quick estimates are needed.
✔ Flexibility: Can be applied to a wide range of projects, especially novel ones.
✔ Contextual Insights: Experts can provide insights based on real-world conditions and specific nuances that data-driven models might miss.
✔ Risk Awareness: Experts are often able to identify hidden risks or challenges that are not apparent in formal data.
Challenges of Expert Judgment
❌ Subjectivity: The quality of the estimate depends on the expertise and experience of the individual or group.
❌ Bias: Experts may have personal biases or overconfidence in their estimates.
❌ Reliability: Estimates may vary significantly between experts, leading to inconsistency in predictions.
❌ Over-Reliance: Solely relying on expert judgment without cross-checking with data can lead to inaccurate estimates.
Conclusion
Expert judgment is a valuable empirical estimation model that leverages the knowledge and experience of subject matter experts to make informed decisions about project parameters. It is especially useful for novel projects, complex projects, or situations where historical data may be limited or unavailable.
✅ Key Takeaways: ✔ Expert judgment relies on experience and knowledge rather than historical data.
✔ It is useful for projects with uncertainty, novelty, or complexity.
✔ Expert estimates can be subjective, so it’s important to validate and combine estimates to improve accuracy.
