Schedule Domain
ECO Domain: Process Domain — Task 8: Plan and manage schedule Related principles: Focus on Value, Adopt a Holistic View
Definition
Project scheduling provides a plan that represents how and when the project will deliver the products, services, and results defined in the project scope. The schedule serves as a tool for communication and for managing stakeholder expectations, and provides a basis for performance reporting. The project schedule also facilitates the proactive identification of potential delays and risks, enabling timely corrective actions to keep the project on track.
Schedule management includes the processes required to oversee the project’s timely completion. The detailed project schedule should be flexible throughout the project to adjust for the knowledge gained, increased understanding of risks and external influences, and value-added activities. With project timelines continuously shrinking, a growing number of practitioners prepare detailed schedules progressively as their projects unfold — initially outlining broad milestones and key activities, then refining and expanding as more information becomes available. A well-known technique that supports this approach is rolling wave planning.
Key Concepts
Project Schedule
The project schedule is an output of a schedule model that presents linked activities with planned dates, durations, milestones, and resources. It may include start and finish dates; duration (total number of work periods required to complete an activity or WBS component, expressed in hours, days, or weeks); milestones (significant points or events); and resources.
Estimate
An estimate is a quantitative assessment of a variable’s likely amount or outcome, such as project effort or duration. Effort is the number of labor units required to complete a schedule activity or WBS component. Duration is the number of work periods needed to complete individual activities with the estimated resources.
Schedule Baseline
The schedule baseline is the approved version of a schedule model that can be changed using formal change control procedures and is used as the basis for comparison to actual results. The level of formality on change control tends to be more rigid on predictive projects and more flexible — or even nonexistent — on adaptive/agile projects.
Schedule Flexibility
Flexibility is essential for adapting to changes, managing risks, and optimizing resource allocations. Flexibility enhances team morale, supports incremental delivery, and helps ensure higher-quality outcomes.
Schedule Forecasts
Schedule forecasts are estimates or predictions of conditions and events in the project’s future based on information and knowledge available at the time the schedule is calculated. Forecasts predict a timeline based on current progress, performance trends, and other project information. Forecasts are updated and reissued based on work performance obtained as the project is executed.
Actual Duration
The actual duration is the time, in calendar units, between the actual start date of the schedule activity and the data date of the project schedule (if the activity is in progress), or the actual finish date (if the activity is complete).
Project Schedule Network Diagrams
A project schedule network diagram is a graphical representation of the logical relationships (dependencies) among the project schedule activities. Sequencing can be performed using project management software. Every work package and activity, except for the first and last, should be connected to at least one predecessor and at least one successor, with an appropriate logical relationship.
Processes
Plan Schedule Management
Establishes policies, procedures, and documentation for designing, developing, managing, performing, and maintaining the schedule throughout the project.
| Field | Detail |
|---|---|
| Key inputs | Project charter, project management plan (scope management plan), development approach, EEFs, OPAs |
| Key tools | Expert judgment, data analysis (alternative analysis), meetings |
| Key outputs | Project management plan updates (schedule management plan — includes release/iteration length, level of accuracy, units of measurement, control thresholds, rules of performance measurement, reporting formats) |
Develop Schedule
Analyzes sequences, durations, resource requirements, and schedule constraints to create a schedule model for project execution and monitoring and controlling. Schedule development is an iterative process with four steps: (1) Define activities, (2) Determine sequence, (3) Estimate effort and duration, (4) Adjust.
Step 1 — Define activities: Identify and document specific actions to be performed to produce project deliverables. Artifacts: activity list, activity attributes, milestones.
Step 2 — Determine sequence: Determine the logical sequence in which work will be carried out — dependencies and relationships (finish-to-start, start-to-start, finish-to-finish, start-to-finish). Lead or lag time between activities may be needed.
Step 3 — Estimate effort and duration: Determine the number of work periods needed to complete each activity with estimated resources. Techniques include: expert judgment, Delphi technique, analogous estimating, parametric estimating, PERT, bottom-up estimating, planning poker, story points, T-shirt sizing. Factors affecting duration: law of diminishing returns, number of resources, advances in technology, cognitive bias (planning fallacy, Hofstadter’s law, end-of-story illusion).
Step 4 — Adjust: Review the draft schedule; apply techniques to adjust (schedule compression, resource leveling) to find alternative schedule options.
| Field | Detail |
|---|---|
| Key inputs | Project charter, project management plan (scope management plan), development approach, project documents (activity list, activity attributes, assumption log, basis of estimates, duration estimates, lessons learned register, milestone list, schedule network diagrams, team assignments, resource calendars, resource requirements, Risk Register), agreements, EEFs, OPAs |
| Key tools | Expert judgment, decomposition, rolling wave planning, precedence diagramming method, logical relationships, leads and lags, dependency determination, estimation techniques, reserve analysis, data analysis (what-if analysis, simulation, alternative analysis), voting, schedule network analysis, schedule compression, critical path method, critical chain method, resource optimization (resource leveling), PMIS, agile release planning |
| Key outputs | Schedule baseline, project schedule, schedule data, project calendars, change requests, project management plan updates, project document updates |
Monitor and Control Schedule
Monitors the status of the project to update the project schedule and manages changes to the agreed-upon schedule. Maintaining a realistic schedule throughout the project duration is the key benefit.
Predictive focus: Determine status of project schedule; influence factors that create schedule changes; reconsider necessary schedule reserves; determine if the overall schedule has changed; manage actual changes as they occur. Any change to the schedule baseline requires formal integrated change control.
Adaptive focus: Determine status by comparing total work delivered and accepted against estimates for the elapsed time cycle; conduct retrospectives for correcting and improving processes; reprioritize remaining work plan (backlog); determine velocity (rate deliverables are produced, validated, and accepted per iteration, typically 2-week or 1-month work cycles); manage actual changes as they occur.
| Field | Detail |
|---|---|
| Key inputs | Project management plan (schedule management plan, scope baseline, performance measurement baseline/Integrated Baseline), product backlog, project documents (lessons learned register, project calendars, project schedule, resource calendars, Risk Register, schedule data), work performance data, EEFs, OPAs |
| Key tools | Data analysis (Earned Value Management (EVM), burnup/burndown chart, performance reviews, trend analysis, variance analysis, what-if scenario analysis), critical path method, critical chain method, PMIS, resource optimization, leads and lags, schedule compression, branch and bound, velocity, daily coordination meetings, sprint reviews, backlog refinement |
| Key outputs | Work performance information, schedule forecasts, change requests, project management plan updates (schedule management plan, schedule baseline, cost baseline, performance measurement baseline), project document updates (assumption log, basis of estimates, lessons learned register, project schedule, resource calendars, risk register, schedule data) |
Tailoring Considerations
- Life cycle and development approach selection — Predictive: schedule defined up front with comprehensive timeline, clear milestones, dependencies, and critical paths; changes go through formal change management. Adaptive: timeboxed schedules that adapt to changes in scope and priorities. Hybrid: high-level predictive schedule for key milestones combined with adaptive sprints for high-change components; other components may use Kanban or critical path method.
- Product and deliverable attributes — High-criticality projects require more detailed and frequent schedule updates. New or innovative technologies may require more iterative scheduling due to uncertainty.
- Project team attributes — Large, dispersed teams need more sophisticated scheduling tools and regular updates. Experienced teams may use a high-level schedule; less-experienced teams need more detailed step-by-step plans.
- Culture — Risk-averse cultures prefer detailed, fixed schedules; adaptive cultures embrace more fluid schedules. Industry culture matters (pharmaceutical = strict; technology = more aggressive on risk). High stakeholder trust enables more flexible scheduling.
- Project environment — Megaprojects vs. small projects differ in level of detail and frequency of updates. Projects with aggressive timelines or critical deadlines require more rigorous scheduling.
- Scheduling approaches and methods — Critical path method, critical chain method, location-based scheduling (LBS), lean scheduling (Last Planner System), Gantt charts, Kanban. LBS allocates quantities to locations considering production rates and crew sizing. Lean scheduling minimizes waste through pull-planning sessions with master scheduling, phase scheduling, and look-ahead planning.
Domain Interactions
The Schedule performance domain closely interacts with all other performance domains. The Scope, Schedule, and Finance performance domains are closely linked — changes in any one will likely impact the others. At the beginning of the project, the expected outcomes are identified and a high-level schedule is developed to achieve these results. Depending on the selected development approach and life cycle, intensive scheduling may be conducted up front and then adjusted, or just-enough scheduling may be applied at various points throughout the project with the expectation that plans will evolve.
The duration of the project depends on its scope, cost, resources, and quality. Each of these factors can cause the schedule to become longer or shorter. While the project outcome is directly dependent on Scope, Schedule, and Finance, these domains are also in parallel to, and indirectly connected with, the Stakeholders, Resources, and Risk performance domains in order to maintain balance under the Governance Domain.
| Direction | Domain | Nature of interaction |
|---|---|---|
| Schedule ↔ | Scope Domain | Scope defines the work; any scope change directly impacts schedule duration and sequencing; Scope and Schedule baselines form part of the performance measurement baseline together |
| Schedule ↔ | Finance Domain | Budget limits resource availability and schedule compression options; schedule overruns drive cost overruns; cost and schedule baselines are interdependent in the PMB |
| Schedule ↔ | Governance Domain | Governance approves schedule baseline changes through integrated change control; value proposition is often time-sensitive so governance can accelerate or slow execution |
| Schedule ↔ | Stakeholders Domain | Stakeholders are involved in schedule development; low stakeholder involvement leads to unrealistic schedules; schedule communicates delivery expectations |
| Schedule ↔ | Resources Domain | Schedule depends on right resources at right times; resource availability directly affects durations and sequencing; resource leveling may extend the schedule |
| Schedule ↔ | Risk Domain | Identified risks drive schedule reserves (float, contingency); risk responses may add activities that affect the schedule; delays trigger risk escalation |
Check Outcomes
Table 2-7 from PMBOK8 §2.3.5:
| Outcome | How to check |
|---|---|
| Scheduling approaches are consistent with the project deliverables | Align the schedule with the development approach for deliverables (predictive, adaptive, or hybrid) |
| The project life cycle consists of phases that connect business and stakeholder value from beginning to end | Represent all project work — from launch to close — in project phases; ensure phases include appropriate exit criteria |
| A holistic approach to delivering project outcomes is developed | Select and develop a delivery schedule that demonstrates the project is planned in a holistic manner with no gaps or areas of misalignment |
| Schedule documentation is complete | Ensure schedule documentation includes all essential elements: task dependencies, durations, resource allocations, and milestones, based on the development approach selected |
| Scheduling tools and techniques are used | Monitor whether the team employed appropriate scheduling tools (e.g., project management software) and techniques (e.g., critical path method) during schedule development |
| Stakeholders are involved in schedule development | Check the level of participation from key stakeholders (client, team members) during scheduling; low involvement may lead to an unrealistic or poorly developed schedule |
| Sufficient buffers are built in for known-unknowns | Check that major project constraints and known risks are factored into the schedule by providing sufficient floats, contingency reserves, or alternate activity network strategies such as secondary plans |
Exam angle
- Estimate types for duration: Exam scenarios present a PM needing a fast estimate — analogous estimating uses historical data (less accurate, faster); parametric uses statistical relationship; bottom-up is most accurate but most time-consuming; wrong answers choose bottom-up when the exam context specifies limited time or early-stage planning
- Critical path vs. critical chain: Critical path = longest path through the network (sequence of activities); critical chain = critical path adjusted for resource constraints plus feeding and project buffers — wrong answers confuse them or say critical chain ignores resources
- Schedule compression techniques: Crashing = adding resources to shorten critical path (increases cost); fast-tracking = overlapping sequential activities (increases risk) — wrong answers apply crashing when the scenario specifies no additional budget, or apply fast-tracking when activities have true mandatory dependencies
- Adaptive schedule monitoring: Velocity (story points per sprint) and burnup/burndown charts replace CPI/SPI in adaptive contexts — wrong answers apply EVM metrics to a pure agile scenario
- Rolling wave planning: Not a sign of poor planning — PMBOK8 explicitly endorses progressive elaboration of detailed schedules as a legitimate approach when details are evolving or timelines are shrinking
- Cognitive bias in estimating: Planning fallacy (underestimating), Hofstadter’s law (it always takes longer than you think, even accounting for this), end-of-story illusion — exam tests awareness that estimates from people closest to the work are preferred AND that biases must be acknowledged