Capacity, dependencies, and forecasting | IT Project Management: from business need to operations

Concept and mechanism

Effort and duration are different measures. Ten person-days of work do not guarantee completion in ten calendar days: dependencies, availability, skills, approvals, and operational windows constrain sequencing. Break work into small deliverables with owners and completion criteria. Confirm availability with the teams providing it, including support, leave, and other initiatives. In a hybrid role reserving 25% for project work, twenty working days provide five theoretical project person-days before interruptions and other constraints. Treating that person as fully available would create a commitment incompatible with the service they must also maintain.

Guided application

In an original exercise, three people available for ten days at 25% provide 7.5 person-days, assuming equivalent availability and no other losses. This sum does not remove a dependency that only one specialist can resolve. Keep actual effort and remaining estimate separate. If 18 person-days have been used and 16 remain, the forecast is 34 against a baseline of 30: the forecast overrun is four. Update the forecast and present options, such as approved scope reduction, changed sequencing, or added capacity. Do not silently change the baseline to erase variance. Record the authorized decision and update linked plans, including support coverage during execution.

IN PRACTICE

18 actual + 16 remaining = 34 forecast; 34−30 = 4 person-days above baseline.

Common pitfalls

Effort as duration;100% allocation; forecast as approval; spent budget as completed work.

Related topics: Mandate, scope, and acceptance · Risk, change, and architecture decisions · Governance, suppliers, and communication

Take this idea with you

Plan actual capacity and expose assumptions and remaining forecast.

Create account

Reference: PM²-PM Highlights · PM² reference practices and cloud operational governance; primary guidance reviewed 2026-09-30