Schedule Management
Time is the one resource you can never recover
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Overview
Schedule Management is one of the most calculation-heavy knowledge areas on the exam. Beyond the formulas, it requires conceptual understanding of how activities relate to each other through dependencies, how the critical path is determined, and which techniques are available when the schedule needs to be compressed. Every schedule question ultimately comes back to the critical path: the longest path through the network with zero total float.
The scheduling process begins with defining activities (decomposing work packages into the discrete tasks needed to produce them), sequencing those activities using dependency types (Finish-to-Start, Start-to-Start, Finish-to-Finish, Start-to-Finish), estimating durations using techniques like PERT or analogous estimation, and then developing a schedule model using Critical Path Method (CPM) or other approaches.
When the schedule needs to be compressed, the PM has two primary options: crashing (adding resources to critical path activities to shorten duration — increases cost, reduces risk) or fast-tracking (doing activities in parallel that were originally planned sequentially — does not increase cost but does increase risk). Crashing should be applied to critical path activities first, targeting the least cost increase per unit of time saved.
Must Know at a Glance
| Term / Concept | Definition |
|---|---|
| Critical Path | The longest path through the project network. Activities on the critical path have zero total float. |
| Total Float (Slack) | Amount of time an activity can be delayed without delaying the project end date. Zero on critical path. |
| Free Float | Amount of time an activity can be delayed without delaying the early start of any successor activity. |
| PERT Estimate | (Pessimistic + 4×Most Likely + Optimistic) / 6. Weighted average favoring the most likely outcome. |
| Standard Deviation (PERT) | (Pessimistic − Optimistic) / 6. Measures uncertainty in the duration estimate. |
| Crashing | Adding resources to critical path activities to shorten duration. Increases cost; reduces schedule risk. |
| Fast Tracking | Doing activities in parallel that were planned sequentially. Does not increase cost; increases risk. |
| Schedule Baseline | Approved version of the schedule model; used for comparing actual vs. planned performance. |
| Milestone | A significant point or event in the project. Has zero duration. |
| Leads and Lags | Lead = acceleration of a successor activity. Lag = deliberate delay added to a dependency. |
Process Sequence
These processes run in order — each one builds on the outputs of the previous.
- 1
Plan Schedule Management
Establishes policies and procedures for planning, executing, and controlling the schedule.
- 2
Define Activities
Decomposes work packages into the specific actions required to produce project deliverables.
- 3
Sequence Activities
Identifies and documents relationships among project activities; produces the network diagram.
- 4
Estimate Activity Durations
Approximates the number of work periods needed to complete individual activities.
- 5
Develop Schedule
Analyzes activity sequences, durations, resources, and constraints to produce the schedule model.
- 6
Control Schedule
Monitoring schedule status; managing changes to the schedule baseline.
Key Formulas
PERT Duration Estimate
tE = (P + 4M + O) / 6
P = Pessimistic, M = Most Likely, O = Optimistic. Weighted average giving 4× weight to the most likely.
PERT Standard Deviation
σ = (P − O) / 6
Measures uncertainty spread. Larger σ = higher uncertainty in the estimate.
PERT Variance
σ² = [(P − O) / 6]²
Square of standard deviation. Used for calculating total path variance.
Total Float
TF = LS − ES or TF = LF − EF
LS = Late Start, ES = Early Start, LF = Late Finish, EF = Early Finish.
Free Float
FF = ES(successor) − EF(current activity)
Amount of time an activity can slip without affecting its successor's early start.
Exam Strategy
How to approach these questions
Schedule compression questions are common. The exam will describe a schedule that is behind and ask what to do: crashing (add resources = more cost, less risk) or fast-tracking (overlap activities = more risk, same cost). If the question says budget is constrained, fast-tracking is the answer. If it says risk must be minimized and cost is available, crash. Remember: only crash critical path activities. Critical path is the longest path — activities with zero float. If asked to identify the critical path, it is the path with the longest total duration.
Common Mistakes
- ✕Thinking the critical path is the shortest path — it is the longest path with zero float.
- ✕Confusing total float (delays the project) with free float (delays only the next activity).
- ✕Applying crashing to non-critical activities — only critical path activities affect the project end date.
- ✕Forgetting that fast-tracking increases risk even though it doesn't increase direct cost.
All 35 Topics in This Domain
Click any topic for the full explanation, key points, exam tips, and FAQs.
Plan Schedule Management
Plan Schedule Management is the process of establishing the policies, procedures, and documentation for planning, developing, managing, executing, and controlling the project schedule.
Schedule Management Plan
The schedule management plan is a component of the project management plan that establishes the criteria and activities for developing, monitoring, and controlling the schedule.
Define Activities
Define Activities is the process of identifying and documenting the specific actions to be performed to produce the project deliverables.
Activity List
The activity list is a comprehensive list of all schedule activities required on the project, including an activity identifier and a scope of work description for each activity.
Activity Attributes
Activity attributes are additional details associated with each schedule activity that extend the description beyond what is in the activity list.
Milestone List
A milestone list identifies all project milestones and indicates whether the milestone is mandatory (required by contract) or optional (based on project requirements or historical information).
Sequence Activities
Sequence Activities is the process of identifying and documenting relationships among the project activities.
Precedence Diagramming Method (PDM)
The Precedence Diagramming Method (PDM) is a technique used to construct a schedule model in which activities are represented by nodes and are graphically linked by logical relationships to show the sequence of activities.
Finish-to-Start (FS) Dependency
A Finish-to-Start (FS) dependency is a logical relationship in which a successor activity cannot start until a predecessor activity has finished.
Start-to-Start (SS) Dependency
A Start-to-Start (SS) dependency is a logical relationship in which a successor activity cannot start until a predecessor activity has started.
Finish-to-Finish (FF) Dependency
A Finish-to-Finish (FF) dependency is a logical relationship in which a successor activity cannot finish until a predecessor activity has finished.
Start-to-Finish (SF) Dependency
A Start-to-Finish (SF) dependency is a logical relationship in which a successor activity cannot finish until a predecessor activity has started.
Leads and Lags
A lead is the amount of time a successor activity can be advanced with respect to a predecessor activity. A lag is the amount of time a successor activity must be delayed with respect to a predecessor activity.
Mandatory Dependencies
Mandatory dependencies are those that are legally or contractually required or inherent in the nature of the work, often involving physical limitations.
Discretionary Dependencies
Discretionary dependencies are established by the project team based on knowledge of best practices, preferred sequencing, or past experience, even though other sequences are possible.
External Dependencies
External dependencies involve a relationship between project activities and non-project activities that are outside the project team's control.
Internal Dependencies
Internal dependencies involve a relationship between project activities that are within the project team's control.
Estimate Activity Durations
Estimate Activity Durations is the process of estimating the number of work periods needed to complete individual activities with the estimated resources.
Analogous Estimating
Analogous estimating uses historical data from similar past activities or projects as the basis for estimating the duration or cost of a current activity or project.
Parametric Estimating
Parametric estimating uses a statistical relationship between historical data and other variables to calculate an estimate for activity parameters such as cost, budget, and duration.
Three-Point Estimating (PERT)
Three-point estimating uses three estimates (optimistic, most likely, and pessimistic) to define an approximate range for an activity's duration or cost, improving accuracy by considering estimation uncertainty.
Bottom-Up Estimating
Bottom-up estimating is a method of estimating project duration or cost by aggregating the estimates of the lower-level components of the work breakdown structure.
Develop Schedule
Develop Schedule is the process of analyzing activity sequences, durations, resource requirements, and schedule constraints to create the project schedule model for project execution, monitoring, and controlling.
Critical Path Method (CPM)
The Critical Path Method (CPM) is a schedule network analysis technique used to estimate the minimum project duration and determine the amount of scheduling flexibility (float) on the logical network paths within the schedule model.
Critical Path
The critical path is the longest sequence of activities in a project schedule network diagram that determines the shortest possible project duration.
Float (Total Float and Free Float)
Total float is the amount of time an activity can be delayed from its early start without delaying the project finish date. Free float is the amount of time an activity can be delayed without delaying the early start of any successor activity.
Schedule Compression
Schedule compression is a technique used to shorten or accelerate the project schedule duration without reducing the project scope.
Crashing
Crashing is a schedule compression technique in which additional resources are added to critical path activities to reduce their duration at the least additional cost.
Fast Tracking
Fast tracking is a schedule compression technique in which activities or phases normally done in sequence are performed in parallel for at least a portion of their duration.
Resource Leveling
Resource leveling is a resource optimization technique in which adjustments are made to the project schedule to keep resource usage at or below a defined limit, often resulting in a longer project duration.
Resource Smoothing
Resource smoothing is a resource optimization technique that adjusts activities within their available float so that resource requirements do not exceed predefined limits, without changing the project end date.
Gantt Chart
A Gantt chart is a bar chart that presents schedule information with activities listed on the vertical axis, dates shown on the horizontal axis, and activity durations shown as horizontal bars placed according to start and finish dates.
Milestone Chart
A milestone chart is a schedule presentation that identifies only the start or completion of major deliverables and key external interfaces, displaying milestones on a timeline.
Schedule Baseline
The schedule baseline is the approved version of the schedule model that is used as a basis for comparison with actual results to determine if corrective or preventive action is needed.
Control Schedule
Control Schedule is the process of monitoring the status of the project to update the project schedule and manage changes to the schedule baseline.
Related Domains
Cost Management
Estimating, budgeting, and controlling costs — earned value management, reserves, and forecasting.
Scope Management
Defining and controlling what is (and isn't) included in the project — WBS, requirements, scope creep.
Risk Management
Identifying, analyzing, and responding to project risks — risk register, response strategies, and monitoring.
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