Purpose
The purpose of this guide is to provide lean Project Managers with practical, repeatable methods for estimating effort and duration of work packages defined in the WBS. Estimation is one of the most challenging aspects of project planning, especially in lean teams (1–3 members) where resources are limited, and overruns have significant impacts. This guide equips PMs with three proven techniques—Expert Judgment, Analogous Estimation, and 3-Point Estimation—that can be applied consistently across Memorres projects.
The guide balances simplicity with rigor. It avoids over-engineered estimation methods unsuitable for lean teams but ensures enough structure to produce defensible estimates. By applying these techniques, Project Managers can develop realistic plans, reduce the risk of over-promising, and provide sponsors with transparent reasoning for effort and timeline commitments.
Scope
This guide applies to all Memorres projects during the Planning phase, after the WBS & Dictionary are completed and before baseline schedules are approved. It covers estimation practices at the governance level, ensuring that each work package has an evidence-based estimate of effort and/or duration.
The scope includes:
- Explaining three estimation methods (Expert, Analogous, 3-Point).
- Providing guidance on when and how to use each method.
- Offering examples relevant to software/digital transformation projects.
- Linking estimation practices to downstream documents (estimation sheets, schedules, resource plans).
The guide does not prescribe detailed engineering estimates or agile story-pointing, which are delivery-level practices. Responsibility for applying these practices rests with the Project Manager, with inputs from SMEs, stakeholders, and PMO oversight.
Main Section
Table 1: Estimation Methods Overview
| Estimation Method | Principle | Application Guidance | Example |
| Expert Judgment | Relies on the knowledge of experienced SMEs or project managers. | Use when domain expertise is available; document rationale; cross-check with historical data. | SME estimates 40 hours for module design based on prior experience. |
| Analogous Estimation | Uses historical data from similar past projects. | Best for early-stage estimates; requires access to MIC records or prior project data. | Past portal redesign took 300 hours; current project estimated at 280–320 hours. |
| 3-Point Estimation | Considers optimistic (O), pessimistic (P), and most likely (M) estimates to calculate expected effort using (O + 4M + P)/6. | Use when uncertainty exists; documents variability; helps communicate risk. | O = 20 hrs, M = 30 hrs, P = 50 hrs → Expected = 32 hrs. |
Narrative Guidance
Expert Judgment
Expert judgment is efficient for lean teams where SMEs have deep experience with similar projects. The PM must ensure the rationale is documented to avoid reliance on undocumented assumptions. Expert estimates should be validated against WBS Dictionary deliverables and, where possible, cross-checked with historical MIC data.
Analogous Estimation
Analogous estimation is most useful when little detail is available. By comparing to past projects of similar scope, PMs can provide early estimates that are realistic and defensible. This method requires a strong knowledge base in MIC and disciplined recordkeeping from prior projects. While less precise than other methods, it provides quick directional estimates.
3-Point Estimation
3-Point Estimation is effective when uncertainty is high or when work packages are influenced by external dependencies. By capturing optimistic, most likely, and pessimistic values, PMs communicate the range of possible outcomes and quantify risk. This method is especially suitable for projects involving integrations, vendor dependencies, or first-time activities.
Closing Note & Cross-References
The Estimation Practices Guide ensures Memorres projects apply structured, transparent, and repeatable estimation methods rather than ad hoc guesses. Lean PM teams should select the most appropriate method for each work package based on available data and uncertainty. Once estimates are derived, they must be recorded in the Effort & Duration Estimation Sheet, linked to the WBS Dictionary, and validated with stakeholders before baselining.