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What is WideBand Delphi Estimation ?

 

WideBand Delphi  (WBD) estimation approach is a technique that was developed in the 1940s at Rand Corporation. This approach involves a team of experts preparing individual estimates for a project, similar to the consensus-based approach for estimation. The estimation approach is a more advanced version of the Delphi method, where the estimation team uses statistical methods to refine and improve the estimates.

 

The WBD estimation approach starts with the same steps as the consensus-based approach, where the project manager selects a team and a moderator, and the team consists of 3-7 team members with representation from all groups, such as development, testing, etc. The moderator should be familiar with the Delphi process, and it is ideal to have the project manager as part of the estimation team. However, the project manager should not be the moderator as he will have a stake in the outcome of the estimation.

 

Steps Involved in Delphi Estimation

 

The first step is the planning phase, where the kickoff meeting takes place. During the kickoff meeting, the team explains the Delphi process, reviews the vision and scope document or any supporting documents as prerequisites, and discusses the goals of the estimation session. The team then brainstorm and notes down the assumptions, generates the initial work breakdown structure (WBS), and decides upon the unit for estimation.

 

The next step is individual estimation, where each estimator estimates the time required for each task, adds any additional tasks to the WBS, and includes any missing assumptions. The difference in the WBD approach is that each estimator also provides a range of estimates for each task, including an optimistic estimate, a pessimistic estimate, and a most likely estimate.

 

The third step is the estimation meeting, where the moderator shares the estimates so that estimators can see the range of estimates. The individual estimates are not shared, and the team members revise estimates based on group discussions. The estimates are revised until no estimator wants to change his/her estimates, and the estimators agree that the estimates are acceptable.

This method offers the advantage of continuous estimation refinement throughout the project’s lifecycle. Initial estimates, even if rough, can evolve with more data and improved understanding. Having consistent estimators streamlines the process, taking advantage of increased knowledge, modified assumptions, and architectural insights. The refined estimate may narrow down the range, but it’s not guaranteed to fall within the previous estimate. If it surpasses it, it serves as an early risk signal that requires immediate attention from the project manager.

 

In the WBD approach, the moderator also uses statistical methods to refine and improve the estimates. The moderator calculates the average of the most likely estimates and determines the standard deviation of the estimates. The standard deviation is used to calculate the optimistic and pessimistic estimates. The moderator then asks the estimators to provide additional estimates based on the optimistic and pessimistic estimates.

 

Example of Delphi Estimation Technique

 

An example of the WBD estimation approach is when there are three estimators, A, B, and C, who are told to prepare the time required to prepare test scenarios for a project. The initial estimations provided were A – 18 Hours, B – 38 Hours, and C – 58 Hours. The moderator then calculates the average estimate as 38 hours and returns this with their original estimates to the estimators.

 

 

Figure: Iterations and Estimated Effort

 

The estimators then meet and discuss the estimates, and the initial estimations provided were A – 31 Hours, B – 32 Hours, and C – 33 Hours. The moderator then calculates the average estimate as 32 hours and asks the estimators if they agree with this as the estimate. The moderator also calculates the optimistic and pessimistic estimates based on the standard deviation of the estimates.

 

The final step is to assemble tasks and review results, where the project manager works with the team and collects the estimates from team members, compiles the final WBS, estimations, and assumptions, and reviews the final estimates with the estimation team. You can find additional details of the technique by reading this e-book From Guesswork to Accuracy: Mastering Software Test Estimation

 

Pros and Cons of  WBD Technique:

 

The Wideband Delphi technique has several advantages that make it an effective estimation method. One of the primary advantages is that it is a consensus-based method, which ensures that all team members are in agreement on the estimates. This consensus also helps to reduce the risk of errors and ensures that the estimates are reliable.Another advantage of the Wideband Delphi technique is that it involves the participation of experienced professionals who are familiar with the project and its requirements. This ensures that the estimates are valid and that the team is able to provide accurate information.The Wideband Delphi technique also allows for anonymity, which ensures that team members are not influenced by the opinions of more powerful or higher-ranking members.

 

This anonymity also helps to reduce the risk of bias and ensures that the estimates are based on objective information.However, the Wideband Delphi technique also has some disadvantages. One of the primary disadvantages is that it requires management support and buy-in. Without the support of management, the technique may not be successful.Another disadvantage of the Wideband Delphi technique is that it can be time-consuming. The process involves multiple rounds of estimation and discussion, which can take several days or even weeks to complete. This can be a challenge for projects with tight deadlines.

Pros:

 

1. Consensus-Based Estimation: The  technique is a method for reaching a consensus when estimating effort.
2. Effective Time Estimation: It is particularly helpful when estimating the time needed for a task. This can be used for any projects or tasks like software development, customer support, quality assurance etc.
3. Involvement of Experienced Individuals: It involves experienced team members who provide individual estimates, enhancing the reliability of the results.
4. Valid Estimates: The estimates come from the people who will actually perform the work, ensuring the validity of the estimates.
5. Anonymity and Confidence: Anonymity is maintained throughout the process, allowing everyone to express their estimates confidently.
6. Simplicity: It is a straightforward technique.
7. Documentation of Assumptions: Assumptions are documented, discussed, and agreed upon, enhancing clarity.

Cons:

 

1. Need for Management Support: Successful implementation of this technique requires support from management.
2. Possibility of Unfavorable Results: The estimation results may not always align with what management desires to hear.

 

Applications and Variations

The Wideband Delphi technique has been widely used in various industries, including software development, sales, and marketing forecasts. It is particularly useful for estimating effort and time, as it ensures that all team members are in agreement on the estimates.The Wideband Delphi technique can also be adapted for use in Scrum projects by combining it with Monte Carlo simulation. This combination helps to provide more accurate estimates and ensures that the project is on track.

 

Below are detailed considerations and guidelines to ensure its effective application:

Clear Communication

Clear communication is paramount in the Wideband Delphi technique, as it involves multiple rounds of estimation and feedback among team members. Ensuring that all participants have a comprehensive understanding of the process and their specific roles is crucial.

1. Orientation Sessions: Conduct thorough orientation sessions where the process is explained in detail. This helps in setting clear expectations and resolving any initial queries.
2. Ongoing Updates: Regular updates should be provided to all participants about the progress and next steps. This continuous flow of information helps in maintaining engagement and focus.
3. Use of Technology: Leveraging collaborative tools and platforms can facilitate better communication. These tools can provide real-time updates and a centralized repository of information, making it easier for team members to stay informed and aligned.

Established Assumptions

Documenting and agreeing upon assumptions at the outset is critical to avoid misunderstandings and ensure that all participants are on the same page.

1. Initial Workshops: Organize initial workshops to collectively identify and document key assumptions. This collaborative approach helps in surfacing any implicit assumptions that might otherwise go unnoticed.
2. Consensus on Assumptions: Ensure that all team members agree on the documented assumptions. This consensus is vital as it sets the foundation for the entire estimation process.
3. Review and Update: Assumptions should be periodically reviewed and updated as necessary. Changes in project scope or external conditions might necessitate a revision of assumptions, and this should be managed proactively.

Anonymity

Maintaining anonymity is one of the core principles of the Wideband Delphi technique. It helps reduce bias and ensures that the estimates provided are objective and uninfluenced by dominant personalities or group dynamics.

1. Anonymous Feedback Mechanisms: Utilize tools and methods that allow participants to provide their estimates and feedback anonymously. This could include online survey tools or specialized Delphi software.
2. Confidentiality Assurance: Clearly communicate to all participants that their inputs will be kept confidential. This assurance can increase their willingness to provide honest and uninhibited estimates.
3. Independent Facilitation: Having an independent facilitator who manages the process and ensures anonymity can further bolster the integrity of the process. The facilitator can collate and present the estimates without revealing the identities of the contributors.

Consensus

Achieving consensus through iterative rounds of estimation and discussion is fundamental to the Wideband Delphi technique. The goal is to refine the estimates and converge on a value that the group collectively agrees upon.

1. Iterative Rounds: The process typically involves several rounds of estimation. After each round, the estimates are shared (anonymously), and participants are encouraged to revise their estimates based on the group feedback.
2. Structured Discussions: Facilitate structured discussions where participants can explain the rationale behind their estimates. This exchange of perspectives is crucial for understanding different viewpoints and driving towards a consensus.
3. Statistical Aggregation: Use statistical methods to aggregate the estimates from each round. Techniques like the median or mean can help in identifying the central tendency of the estimates, guiding the group towards a consensus.

Documentation

Comprehensive documentation of the process and results is essential for ensuring transparency and accountability. It provides a clear audit trail that can be referenced in the future and helps in continuous improvement of the estimation process.

1. Process Documentation: Document each step of the Wideband Delphi process, including the initial assumptions, the methodology used for estimation, and the communication protocols.
2. Results Recording: Record the estimates from each round, the rationale behind significant changes, and the final consensus value. This detailed recording helps in understanding the evolution of the estimates and the factors influencing them.
3. Post-Process Review: Conduct a post-process review to evaluate the effectiveness of the Wideband Delphi technique. Gather feedback from participants on what worked well and what could be improved. Document these insights to refine the process for future applications.

Conclusion

The Wideband Delphi technique is a consensus-based estimation method that has been widely used in various industries. It involves a structured communication framework that fosters collaboration and reflection among a team of experts. The technique has several advantages, including the participation of experienced professionals, anonymity, and the ability to reduce the risk of errors.However, the Wideband Delphi technique also has some disadvantages, including the requirement for management support and the potential for time-consuming processes. Despite these disadvantages, the technique remains an effective method for estimating tasks and ensuring that projects are on track.By understanding the Wideband Delphi technique and its applications, project managers can make informed decisions about the estimation process and ensure that their projects are successful

 Frequently Asked Questions (FAQ) on WideBand Delphi Estimation

1. What is the Delphi Estimation Technique?

The Delphi Technique is a structured and consensus-based estimation method used in project management and software development. It involves a group of experts providing individual estimates for a particular task or project, followed by a facilitated discussion to reach a consensus estimate.

 2. How does the Delphi Technique work?

Here’s a simplified breakdown of the process:
– A group of experts or team members is assembled.
– Each expert provides their independent estimates for the task or project.
– The estimates are collected and discussed.
– The group works together to reach a consensus estimate.
– This process may iterate until a consensus is achieved.

 3. What are the advantages of using the  Technique?

– Consensus-Based Estimation**: It encourages collaboration and consensus among experts.
– Involvement of Experienced Individuals**: Experts in the domain provide estimates, increasing the reliability of results.
– Valid Estimates**: Estimates come from those who will perform the work, ensuring validity.
– Anonymity**: Anonymity is maintained during estimation, allowing for honest input.
– Simple Technique**: It’s a straightforward and easy-to-understand method.
– Documentation of Assumptions**: Assumptions are documented and discussed.

 4. When should the Delphi Technique be used?

– It is useful for estimating project tasks, especially when multiple experts are involved.
– When there is uncertainty or lack of historical data for estimation.
– In situations where consensus among team members is crucial.

 5. Are there any disadvantages to using this technique?

– Management Support: Successful implementation may require support from management.
– Possibility of Unfavorable Results: The consensus estimate may not always align with management’s expectations.

 6. Can the Technique be used for all types of projects?

While it is versatile, the Delphi Technique is particularly beneficial for projects with:
– High uncertainty.
– Diverse teams with varying expertise.
– A need for consensus among team members.

 7. What role does the facilitator play in the  Technique?

The facilitator plays a crucial role in guiding the estimation process. They:
– Ensure the process is followed correctly.
– Manage discussions and conflicts.
– Help the group reach a consensus.
– May iterate the process if consensus is not initially achieved.

 8. How can I ensure the Technique is effective?

– Assemble a diverse group of experts.
– Clearly define the task or project to be estimated.
– Encourage open and honest communication.
– Follow a structured process with a skilled facilitator.
– Document assumptions and agreements.

9. Are there variations of the Delphi Estimation Technique?

Yes, variations exist, including:

– Modified Delphi: Involves feedback and re-estimation rounds.
– Wide Band Delphi with Historical Data: Combines expert estimation with historical data analysis.
– Electronic Delphi: Conducted online, facilitating participation from geographically dispersed experts.

10. Can the Delphi Estimation Technique be used for cost estimation?

Yes, it can be adapted for cost estimation by applying the same consensus-building process to estimate project expenses.

Remember, the effectiveness of the Delphi Technique depends on factors such as the expertise of participants, a well-defined scope, and skilled facilitation.