Concept of 3 Experts
What is the concept fo 3 experts, how does it differ from the planning poker and how are values determined?
Joint effort estimate
The concept of 3 experts is a procedure for estimating expenditure by means of an expert survey. Three experts independently estimate the effort of a process, a work package, a project or a requirement. In contrast to the planning poker, a method frequently used in Scrum to estimate effort, each expert should provide an optimistic, a realistic and a pessimistic effort estimate. In the planning poker, each participant estimates an effort once, with the aim of working out the reasons for the differences in the estimates through subsequent discussion. With the 3-expert concept, the results are compared with each other:
- Differences in the optimistic effort estimates can be an indication of opportunities that are interpreted differently by the experts.
- Differences in pessimistic effort estimates can reveal risks that are assessed differently by the experts.
- Differences in realistic effort estimates can be an indication of individual assumptions that need to be questioned – as with optimistic and pessimistic estimates.
Generally speaking, it is not possible to determine which value (optimistic, realistic or pessimistic) should be included in an appropriate plan. This depends, among other things, on the concrete project requirements, experience or the corporate and project culture. It is important that the concept of 3 experts can reveal different assumptions regarding individual processes or entire projects, boundary conditions and goals, opportunities and risks, tasks, etc. These differences must be addressed as early as possible and taken into account when planning processes, work packages, projects or requirements.