LEARN. PRACTICE. GROW.Capacity that exists in the calendar
In a role combining support and projects, the contractual percentage is a planning assumption rather than a daily guarantee. Start with the days actually available and the agreed project allocation. If someone has four available days and allocates 25% to the project, the period contains one person-day of project capacity. If that 25% already excludes support, do not subtract another 75% reserve. Record included absences, training, shift handover, and incidents. Update the assumption using observed data and confirm any reassignment with the resource owner.
Technical dependencies and competition for one specialist
Two activities can be technically independent and still compete for the same person. Six person-days of network configuration and four person-days of firewall review require twenty working days when one specialist performs both at 50% allocation, with no other constraints. Drawing them in parallel does not create capacity. Identify indivisible work, unavailable periods, and skills that prevent immediate substitution. After resource leveling, recalculate the finish date and float. Document the selected sequence, distinguishing an execution preference from a mandatory technical dependency.
Status date and remaining work
Choose one status date for the update. Separate events that actually happened by that date from work still to be performed. An activity planned for eight days is not necessarily 75% complete after six days: an approval or test may dominate its remaining duration. Request delivery evidence, remaining duration, and unresolved dependencies. Do not record a future forecast as an actual start. If work occurred out of the planned sequence, preserve that fact and revise the remaining logic; rewriting history to tidy the diagram undermines useful tracking.
Critical path, float, and imposed dates
In an example without resource constraints, A takes one day; B takes four and C six, both after A; D takes two and waits for B and C. Earliest completion is day nine and B has two days of float. If B slips three days, completion becomes day ten. Float belongs to the path and should not be independently promised by several teams. A mandatory software date does not shorten durations or remove predecessors. If calculation yields day nineteen against a day-fifteen commitment, report the four-day gap with executable options.
Probability of meeting a date
A deterministic forecast uses one set of durations; it does not by itself express the probability of meeting a commitment. Schedule risk analysis can model duration ranges, shared risks, and dependencies. A P80 date means roughly 80% of modeled outcomes finish by that date under the assumptions. It does not guarantee the project outcome. Do not add task P80 dates or durations to invent an overall P80: correlation and parallelism change the result. Review data credibility before presenting precision, and explain which risks were not modeled.
Prepare a capacity decision
In a fictional fund service, APS incidents consume time reserved for migration. Present observed capacity, remaining work, the affected path, and the next genuinely usable window. Compare alternatives such as phasing an independent deliverable, obtaining a specific skill, or negotiating the date. State who accepts scope changes and who can commit resources. Include additional coexistence costs and effects on support. Close the meeting with a decision, owner, deadline, and assumption that triggers another review. A red status without a decision request reports the problem but does not organize the response.
A has duration 1; B=4 and C=6 follow A in parallel; D=2 waits for both. Without additional constraints, 1+max(4,6)+2=9 days. Delaying B by three days gives 1+max(7,6)+2=10. If B and C require the same person, recalculate using that resource calendar.
Common pitfalls
Subtracting support twice; equating elapsed duration with completed work; leveling resources without recalculating completion; treating P80 as a guarantee; deleting actual dates to conceal a different sequence.
Related topics: Plan effort, capacity, and forecasts · Control costs and close the lifecycle · Dependencies and the critical path
A useful forecast combines logic, resources, status-date evidence, and uncertainty, ending in a decision someone can authorize.
Reference: Schedule Assessment Guide: resource leveling, status and risk · DR Technical Project Manager 2026.4; independent professional curriculum