Three point estimation
A three-point estimate is a method used to estimate the cost or duration of a project task or activity. It is commonly used in project management, and it is particularly important in the construction industry, where projects can be complex and involve many different tasks
It involves using three estimates: an optimistic estimate, a most likely estimate, and a pessimistic estimate.
- The optimistic estimate is the best-case scenario for how long the task will take or how much it will cost.
- The pessimistic estimate is the worst-case scenario.
- The most likely estimate is the estimate it is believed is the most accurate representation of how long the task will take or how much it will cost based on their experience and expertise.
To calculate the three-point estimate, the three estimates are first added together and then divided by three to give an expected value. This expected value can be used to help project managers plan resources and schedule tasks more accurately.
Should cost modelling, Development Guidance, Version 1.0, published by Government Commercial Function in May 2021 states: ‘This technique uses three different estimates of potential costs, the most likely, optimistic and pessimistic profiles. These estimates are then aggregated and averaged to provide estimates that are adjusted for extremes. It is often applied in the context of Monte Carlo simulation to produce probabilistic outputs.’
[edit] Related articles on Designing Buildings
Featured articles and news
Call for greater recognition of professional standards
Chartered bodies representing more than 1.5 million individuals have written to the UK Government.
Cutting carbon, cost and risk in estate management
Lessons from Cardiff Met’s “Halve the Half” initiative.
Inspiring the next generation to fulfil an electrified future
Technical Manager at ECA on the importance of engagement between industry and education.
Repairing historic stone and slate roofs
The need for a code of practice and technical advice note.
Environmental compliance; a checklist for 2026
Legislative changes, policy shifts, phased rollouts, and compliance updates to be aware of.
UKCW London to tackle sector’s most pressing issues
AI and skills development, ecology and the environment, policy and planning and more.
Managing building safety risks
Across an existing residential portfolio; a client's perspective.
ECA support for Gate Safe’s Safe School Gates Campaign.
Core construction skills explained
Preparing for a career in construction.
Retrofitting for resilience with the Leicester Resilience Hub
Community-serving facilities, enhanced as support and essential services for climate-related disruptions.
Some of the articles relating to water, here to browse. Any missing?
Recognisable Gothic characters, designed to dramatically spout water away from buildings.
A case study and a warning to would-be developers
Creating four dwellings... after half a century of doing this job, why, oh why, is it so difficult?
Reform of the fire engineering profession
Fire Engineers Advisory Panel: Authoritative Statement, reactions and next steps.
Restoration and renewal of the Palace of Westminster
A complex project of cultural significance from full decant to EMI, opportunities and a potential a way forward.
Apprenticeships and the responsibility we share
Perspectives from the CIOB President as National Apprentice Week comes to a close.