Wideband Delphi Estimation Technique Vs Planning Poker

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Planning poker Combines three assessment methods: The Wideband Delphi Technique, Analogous Estimation, and WBS. While estimating, there are many different reasons that can cause some issues, so it is important to express estimates in a number of possible outcomes. Few teams actually use Wideband Delphi for their estimates. Most teams use one of its related techniques. That technique is planning poker. It's the most commonly used Agile estimation technique. Check out this course for an in-depth explanation of planning poker.

Wideband Delphi Technique. Wideband Variant of the Delphi Method was originated in the 1970s, by Barry Boehm and John A. The term 'wideband' is used because, compared to the Delphi Method, the Wideband Delphi Technique involved greater interaction and more communication between the participants. Planning Poker is an agile estimating technique which has become very popular in the last few years. It is based on an estimation technique known as Wideband Delphi which was created by the RAND. The technique we use to conduct relative estimation is a game invented by James Grenning and popularized by Mike Cohn called Planning Poker. It is based on a method developed in the 1970s called Wideband Delphi that evolved from an earlier version (Delphi) invented in the 1950s by the RAND Corporation.

Delphi Method is a structured communication technique, originally developed as a systematic, interactive forecasting method which relies on a panel of experts. The experts answer questionnaires in two or more rounds. After each round, a facilitator provides an anonymous summary of the experts’ forecasts from the previous round with the reasons for their judgments. Experts are then encouraged to revise their earlier answers in light of the replies of other members of the panel.

It is believed that during this process the range of answers will decrease and the group will converge towards the 'correct' answer. Finally, the process is stopped after a predefined stop criterion (e.g. number of rounds, achievement of consensus, and stability of results) and the mean or median scores of the final rounds determine the results.

Delphi Method was developed in the 1950-1960s at the RAND Corporation.

Wideband Delphi Technique

In the 1970s, Barry Boehm and John A. Farquhar originated the Wideband Variant of the Delphi Method. The term 'wideband' is used because, compared to the Delphi Method, the Wideband Delphi Technique involved greater interaction and more communication between the participants.

In Wideband Delphi Technique, the estimation team comprise the project manager, moderator, experts, and representatives from the development team, constituting a 3-7 member team. There are two meetings −

  • Kickoff Meeting
  • Estimation Meeting

Wideband Delphi Technique – Steps

Step 1 − Choose the Estimation team and a moderator.

Step 2 − The moderator conducts the kickoff meeting, in which the team is presented with the problem specification and a high level task list, any assumptions or project constraints. The team discusses on the problem and estimation issues, if any. They also decide on the units of estimation. The moderator guides the entire discussion, monitors time and after the kickoff meeting, prepares a structured document containing problem specification, high level task list, assumptions, and the units of estimation that are decided. He then forwards copies of this document for the next step.

Step 3 − Each Estimation team member then individually generates a detailed WBS, estimates each task in the WBS, and documents the assumptions made.

Step 4 − The moderator calls the Estimation team for the Estimation meeting. If any of the Estimation team members respond saying that the estimates are not ready, the moderator gives more time and resends the Meeting Invite.

Step 5 − The entire Estimation team assembles for the estimation meeting.

Step 5.1 − At the beginning of the Estimation meeting, the moderator collects the initial estimates from each of the team members.

Step 5.2 − He then plots a chart on the whiteboard. He plots each member’s total project estimate as an X on the Round 1 line, without disclosing the corresponding names. The Estimation team gets an idea of the range of estimates, which initially may be large.

Poker

Step 5.3 − Each team member reads aloud the detailed task list that he/she made, identifying any assumptions made and raising any questions or issues. The task estimates are not disclosed.

The individual detailed task lists contribute to a more complete task list when combined.

Delphi

Step 5.4 − The team then discusses any doubt/problem they have about the tasks they have arrived at, assumptions made, and estimation issues.

Step 5.5 − Each team member then revisits his/her task list and assumptions, and makes changes if necessary. The task estimates also may require adjustments based on the discussion, which are noted as +N Hrs. for more effort and –N Hrs. for less effort.

The team members then combine the changes in the task estimates to arrive at the total project estimate.

Step 5.6 − The moderator collects the changed estimates from all the team members and plots them on the Round 2 line.

In this round, the range will be narrower compared to the earlier one, as it is more consensus based.

Step 5.7 − The team then discusses the task modifications they have made and the assumptions.

Step 5.8 − Each team member then revisits his/her task list and assumptions, and makes changes if necessary. The task estimates may also require adjustments based on the discussion.

The team members then once again combine the changes in the task estimate to arrive at the total project estimate.

Step 5.9 − The moderator collects the changed estimates from all the members again and plots them on the Round 3 line.

Again, in this round, the range will be narrower compared to the earlier one.

Step 5.10 − Steps 5.7, 5.8, 5.9 are repeated till one of the following criteria is met −

  • Results are converged to an acceptably narrow range.
  • All team members are unwilling to change their latest estimates.
  • The allotted Estimation meeting time is over.

Step 6 − The Project Manager then assembles the results from the Estimation meeting.

Step 6.1 − He compiles the individual task lists and the corresponding estimates into a single master task list.

Step 6.2 − He also combines the individual lists of assumptions.

Step 6.3 − He then reviews the final task list with the Estimation team.

Advantages and Disadvantages of Wideband Delphi Technique

Advantages

Wideband delphi estimation technique vs planning poker software
  • Wideband Delphi Technique is a consensus-based estimation technique for estimating effort.
  • Useful when estimating time to do a task.
  • Participation of experienced people and they individually estimating would lead to reliable results.
  • People who would do the work are making estimates thus making valid estimates.
  • Anonymity maintained throughout makes it possible for everyone to express their results confidently.
  • A very simple technique.
  • Assumptions are documented, discussed and agreed.

Disadvantages

  • Management support is required.
  • The estimation results may not be what the management wants to hear.

Wideband delphi is a process used to obtain an estimate by involving multiple estimators and combining their estimates. It has a complicated name but is a simple and intuitive process for producing better estimates.

Better estimates allow you to better choose and cost projects. A better estimate of the project can allow you to win more business with more competitive bids, and avoid unprofitable projects.

Wideband delphi should acheive a better estimate than individual estimation because it focuses on involving multiple experts, and combining their expertise in a way that achieves a better estimate than a simple mathematical combination of the estimate. In addition it also encourages break down of the item to be estimated into smaller items, another good method to improve the accuracy of the estimates.

How does wideband delphi work?

Wideband delphi is a very simple process. You need an estimation coordinator and a number of estimators. Generally you do not want too many estimators as discussions will be longer and consensus will be more difficult to reach.

Step 1: Kickoff meeting

In the kickoff meeting describe the project to be estimated and its requirements to all estimators. Answer any questions raised to clarify the project as much as possible.

Step 2: Individual estimation

Each estimator breaks down the project into tasks, and estimates the tasks. These individual estimates must be written down.

Step 3: Discussion meeting

Hold a meeting where estimators present their estimates and discuss reasons for the estimates. Because some estimators will see problems or solutions that others did not, the discussion ensures that during the next round of estimation each estimator will take more information into account in their estimates.

Step 4: Repeat

Repeat steps 2 and 3 as many times as necessary to obtain an estimate range with an acceptable level of variation between experts.

Variations

When you understand that the key to wideband delphi is the combination of multiple estimates by discussion, you can easily vary the process to suit your environment. Some simple variations might be:

1. Provide a common task breakdown in the kickoff meeting.

With each estimator working on the same breakdown discussion can be focused on the estimates, rather than being split between estimates and breakdown. Estimators should still be able to add tasks to the breakdown to capture any additional work overlooked in the original breakdown.

2. Perform everything in one meeting.

By completing individual estimates and discussions in the same meeting time can be saved, particularly on small projects. It is still important however that each estimator estimates individually, writes their estimates down, and discussion only takes place after all have finished their individual estimation.

3. Come to a group consensus rather than multiple rounds

You could also have only a single round of estimation, with the discussion afterwards targeted to come to a single group consensus. The consensus can be in the form of a range which can limit the length of the meeting.

Wideband Delphi Estimation Technique Vs Planning Poker For Dummies

Wideband delphi is more robust than a single estimator coming up with a number. It has a number of similarities to agile planning poker, however it is different in that estimates for all tasks are completed up front individually rather than estimating and reaching consensus on each task one at a time.

Wideband Delphi Estimation Technique Vs Planning Poker Rules

You can use wideband delphi to improve the estimates for your next project. TaskTrakz project management software allows you to record your project task breakdown, along with one, two or three point range estimates for each task so you can easily record your wideband delphi estimates, and then execute the project directly on the same task breakdown. Get your free 14 day trial of TaskTrakz here.