The project estimation is a methodical process of arriving at the estimation. The primary input to these are the past numbers in terms resources, hours used for the projected, and lines of codes or functional points achieved. The historical data of this is collected and analyzed to be used in the current estimation technique.
Once the PRD is ready, the Engineering Manager understands the complexity and criticality of the entire project and prepares the draft of the architectural diagram.
The initial architecture will have the major components, their relationships, their dependencies, and attributes. To keep the architecture simple and real the architecture will have around 7 major components (+/- 2). Each component is then distributed to the specialists of those components.
The specialists then will estimate the analysis, design, code, and test for each of the components. The estimate for each component is calculated this way. Estimates of all the components are then added.
Estimate required to integrate all of them will also go through th same cycle and is added to the estimate. This gives us the overall estimate for the project based on previous similar projects and for requirements according to PRD.