Where does this Cone Come From?
The reason for this cone or funnel are the risks, which are present in every project:
- Risks of the project scope: what belongs to the project and what does not (which features, which interfaces, which standards...).
- Technical or more general realization risks: what may not work out
- Estimation risks: general estimation errors, mostly people are too optimistic...
The risks that the project contains also result in the opening of the cone towards the future: the less risks a project contains, the more accurate I can estimate.
Estimate or Promise?
Many estimates start life as a number thrown around at a meeting, as a first order of magnitude, usually with great optimism. This number should not be taken as a promise for the effort of the project.
When we as Solcept really make a promise (e.g. when we offer a fixed price), we put quite a lot of effort into achieving to reach a sufficient accuracy, e.g. we perform a system design phase and a structured estimation.
Why do we do this? Because so we are limiting the risks:
- Scope risks: contained with clear requirements
- Technical risks: contained with architecture and rapid prototype
the remaining risks are identified and are part of the promised scope (called "risk management")
- Estimation risks: contained with structured estimation methodology
How do we Proceed at Solcept?
If at the beginning of a project, you want to have an estimate, we perform a coarse estimate based on the desired functions or assumptions about them and our empirical values for documentation, testing and integration.
After the system design phase, where a system specification and a system architecture are created, we can perform a project estimate, at least on the part that is already clear. This is significantly more accurate. Each next phase can then be estimated this way once the scope of the phase (i.e., the requirements that the product should meet after the phase) is clear.