Estimation

Definition

Estimation is the practice of predicting the effort, time, cost, complexity, or resources needed to deliver a requirement or solution. Business Analysts use estimation to support planning and forecasting, trade-off discussions, prioritization, and roadmap decisions. Estimates are informed forecasts, not guarantees — they should include confidence levels and be revisited as understanding improves.

Inputs

• Defined scope of what is being estimated (requirements, features, or delivery phases)
• Decomposed work items with sufficient detail to estimate
• Historical data from comparable past work where available
• Input from the technical team and subject matter experts
• Documented assumptions and constraints

Outputs

• Effort, time, or cost estimates at agreed granularity
• Confidence levels and documented assumptions
• Inputs to release planning, budgeting, and prioritization decisions
• A basis for scope trade-off conversations with stakeholders

When to Use

• Project planning and roadmap creation where resource or timeline commitments are needed
• Release planning and budgeting
• Prioritization and scope trade-offs when capacity is constrained
• Vendor comparison or build-vs-buy decisions requiring cost inputs

When Not to Use

• When scope is so uncertain that any estimate would be misleading — time-box exploration first
• When estimates will be treated as commitments without confidence ranges — set expectations first
• When the overhead of formal estimation exceeds the value for very small, low-risk items