Unit 8: Overallocations

I. Orientation: Resource Overallocations

A resource overallocation occurs when a work resource is assigned more work than its available capacity permits during a particular time period. In project-management software such as Microsoft Project, overallocations are detected by comparing time-phased assignment work with the resource’s calendar, maximum units, and availability dates. An overallocation is therefore a scheduling conflict, not merely a large total workload.

• Governing principle: A resource is overallocated when required assignment units exceed available capacity at any point in time.
  • If a resource with Max Units = 100% is assigned simultaneously at 60% and 70%, the combined demand is 130%.
  • The overallocation during that overlap is 30%.

Allocation % = (Assigned work rate / Available work rate) × 100

Overallocation % = max(0, Allocation % - Maximum Units %)

• Resource capacity: Maximum Units specifies how much of a resource is available to the project.

  • 100% normally represents one full-time resource.
  • 50% represents half-time availability.
  • 300% may represent a team of three equivalent full-time workers.

• Time dependence: Overallocation is evaluated for individual time periods, not only for the project as a whole.

  • A resource may have only 32 hours of work in a 40-hour week but still be overallocated on Monday if two eight-hour tasks occur simultaneously.
  • Changing the timescale from weeks to days or hours can reveal conflicts hidden by aggregated totals.

• Calendar dependence: Availability is determined by the resource calendar, including working days, shifts, holidays, and exceptions.

  • Eight hours assigned on a four-hour working day creates excess demand even if the resource usually works eight-hour days.

• Common causes: Overallocations typically result from overlapping tasks, excessive assignment units, unrealistic constraints, changed calendars, or assignments added after the schedule was prepared.

• Visual indicators: Microsoft Project commonly displays overallocated resources in red and may show an overallocation indicator beside the resource name.

• Resolution principle: A manager should inspect the conflict before changing the schedule.

  • Typical responses include delaying or splitting a task, replacing a resource, adding capacity, reducing assignment units, changing task logic, or applying resource leveling.
  • Leveling may resolve a conflict by delaying or splitting work, but it does not create additional capacity.

II. Resource Usage View: Time-Phased Work Analysis

The Resource Usage view organizes the schedule by resource and shows each resource’s assignments beneath it. Its time-phased grid makes it the principal view for identifying exactly when an overallocation occurs and which tasks contribute to it.

A. Using The Resource Usage View

The Resource Usage view diagnoses overallocations by connecting each resource to its assigned tasks and workload over time.

• Opening the view: Select the Resource Usage view from the application’s resource-oriented views.

  • The left table lists resources, with task assignments indented below each resource.
  • The right grid displays values such as Work for days, weeks, or other timescale units.

• Reading the hierarchy: The resource summary row aggregates the work from all assignments listed beneath it.

  • If Arun is assigned four hours to Task A and six hours to Task B on Tuesday, the resource row shows ten hours for Tuesday.
  • With an eight-hour calendar, two hours exceed the available capacity.

• Finding highlighted conflicts: Overallocated resource names and conflicting time-phased values are commonly shown in red.

  • Expanding the resource exposes the individual assignments responsible for the total.
  • A red resource row alone identifies the affected resource; the assignment rows explain the cause.

• Adjusting the timescale: The timescale should match the precision required for diagnosis.

  • A weekly view is useful for scanning long projects.
  • A daily or hourly view is needed when assignments overlap for only part of a week or day.
  • Zooming out can conceal short conflicts because workload is aggregated into larger periods.

• Changing displayed details: The time-phased grid can display fields such as Work, Actual Work, Overtime Work, Cost, or Overallocation.

  • The Overallocation detail isolates work that exceeds capacity.
  • Actual Work distinguishes completed effort from remaining scheduled effort.

• Filtering overallocated resources: Applying an overallocated-resource filter reduces a large resource list to the resources requiring attention.

  • Grouping by resource group or department can expose repeated pressure on a specialist team.

• Worked example: A resource available eight hours per day has Task Design scheduled for six hours and Task Review scheduled for four hours on Wednesday.

  • Resource-level work is 6 + 4 = 10 hours.
  • Available work is 8 hours.
  • The Resource Usage grid reveals 2 hours of overallocation and identifies both contributing assignments.

B. Interpretation and Limitations

The view provides detailed evidence, but its values must be interpreted in relation to scheduling rules and management priorities.

• Assignment-level editing: Work or assignment units can be edited where the scheduling model permits, but the effect depends on task type and effort-driven settings.

  • Reducing units may extend duration for a fixed-work task.
  • Reducing work may alter the planned scope rather than merely fix the schedule.

• Conflict versus error: A highlighted overallocation is not automatically a planning mistake.

  • A brief overlap may be intentional, covered by overtime, or acceptable for a pooled resource represented by more than one person.

• Limitation: The view is information-dense and can become difficult to scan when hundreds of assignments are expanded.

  • Filters, grouping, and a suitable timescale are necessary for efficient analysis.

III. Resource Management Toolbar: Commands for Resource Control

The Resource Management toolbar provides direct access to commands used to inspect assignments, move between conflicts, and open resource-focused views. Toolbar contents and button placement vary across Microsoft Project versions, with newer ribbon-based versions exposing equivalent commands through Resource tabs and view controls.

A. Using The Resource Management Toolbar

The toolbar supports a controlled workflow from detecting an overallocated resource to examining and correcting its assignments.

• Displaying the tools: In classic menu-based versions, the toolbar is enabled through the toolbar customization or View menu.

  • Ribbon-based versions place comparable functions under resource management, assignment, leveling, and view commands.

• Navigating conflicts: The next-overallocation command moves the active timescale to the next period in which the selected resource exceeds capacity.

  • This is more reliable than manually scrolling through a long schedule.
  • Repeating the command allows conflicts to be reviewed chronologically.

• Opening allocation information: Resource-oriented view commands provide rapid access to the Resource Usage, Resource Allocation, or Resource Graph displays.

  • The selected resource should remain the focus where the version supports synchronized navigation.

• Managing assignments: Assignment commands allow a manager to add, replace, or remove resources and adjust assignment units.

  • Replacing a scarce specialist with another qualified resource removes the conflict only if the replacement is available and suitable.
  • Removing a resource without preserving required work may leave the task understaffed.

• Accessing resource data: Resource information and notes commands expose calendars, maximum units, rates, availability periods, and documented constraints.

  • Correcting an inaccurate resource calendar may remove a false overallocation.
  • Increasing Maximum Units is valid only when additional real capacity exists.

• Applying leveling controls: Leveling commands can calculate resource-leveling adjustments according to configured options.

  • Manual mode allows changes to be reviewed before recalculation.
  • Automatic mode responds quickly but may move tasks whenever the schedule changes.

B. Operational Discipline and Limitations

Toolbar commands accelerate resource management, but each correction must preserve scope, sequence, cost, and deadline requirements.

• Recommended sequence: Select the resource, navigate to the conflicting period, inspect assignments, choose a feasible correction, and recalculate the schedule.

  • This sequence prevents a global leveling operation from being used before the local cause is understood.

• Verification: After a change, review task finish dates, total slack, critical-path status, cost, and remaining overallocations.

  • A resolved resource conflict may create a milestone delay elsewhere.

• Limitation: A toolbar is only a command surface; it does not determine the most appropriate management decision.

  • Qualification, contractual limits, task priority, and stakeholder commitments remain managerial considerations.

IV. Resource Allocation View: Combined Schedule Diagnosis

The Resource Allocation view is a combination view designed to show resource assignments and their scheduling consequences together. In classic Microsoft Project configurations, it commonly presents Resource Usage in the upper pane and a task-oriented leveling or Gantt display in the lower pane.

A. Using The Resource Allocation View

The Resource Allocation view links an overallocated resource in one pane with the tasks that may need adjustment in the other.

• Selecting a resource: The upper pane lists resources and their assignments, allowing the manager to select the overallocated resource or a particular assignment.

  • The lower pane displays corresponding task bars, dates, dependencies, delay, and available slack.

• Tracing the overlap: Task bars reveal whether conflicting assignments run concurrently and whether either task can move.

  • Two tasks occupying Monday through Wednesday for the same full-time resource visibly explain the overallocated interval.

• Evaluating schedule flexibility: Total slack, free slack, priority, constraints, and successor relationships indicate which assignment can be delayed with the least disruption.

  • A task with two days of free slack may be delayed by one day without affecting its immediate successor.
  • A zero-slack critical task should not be moved casually.

• Using leveling delay: Leveling Delay can postpone an assignment or task by a specified amount without changing its logical predecessor links.

  • A delay of 1 elapsed day and a delay of 1 working day may produce different dates because calendars govern working time.

• Splitting work: Where interruption is operationally acceptable, a task can be split around a higher-priority assignment.

  • Splitting is unsuitable for continuous activities such as a single uninterrupted system migration.

• Checking both panes: After an adjustment, the upper pane confirms whether the overallocation disappeared, while the lower pane shows the effect on task timing.

B. Applications and Limitations

The combination view is most useful when resolving a conflict requires balancing resource capacity against network-schedule consequences.

• Application: It supports local, assignment-aware decisions rather than indiscriminately delaying every task assigned to the resource.

  • Priority, slack, dependencies, and deadlines can be compared before work is moved.

• Application: It helps distinguish a resource problem from a task-logic problem.

  • Incorrect simultaneous start constraints may be better corrected through dependencies than through added leveling delay.

• Limitation: Pane synchronization and displayed fields depend on the software version and customized view definition.

  • A manager must verify which upper and lower views are actually configured.

• Limitation: Manual delays can become obsolete after duration, dependency, or calendar changes.

  • The schedule should be recalculated and rechecked after significant updates.

V. Resource Allocation Graph: Visual Capacity Comparison

A Resource Allocation Graph, commonly represented through the Resource Graph view, plots resource demand against availability over time. It is best suited to recognizing the magnitude, timing, and pattern of overallocations rather than identifying every contributing assignment.

A. Using The Resource Allocation Graph

The graph converts time-phased allocation data into a visual comparison of required and available resource capacity.

• Selecting the resource: Choose a work resource to display its allocation across the project timescale.

  • Navigation controls move between resources while retaining the time period for comparison.

• Reading the axes: The horizontal axis represents time, while the vertical scale represents units, work, or another selected resource measure.

  • A bar reaching 150% for a resource with 100% maximum units indicates demand equal to one and a half full-time equivalents.

• Recognizing overallocated periods: Values above the availability threshold are highlighted, commonly in red.

  • A single spike suggests a short scheduling collision.
  • Repeated peaks suggest recurring parallel assignments.
  • A sustained excess suggests inadequate capacity or an unrealistic baseline plan.

• Changing graph details: Depending on the version, the graph can show Peak Units, Work, Availability, Cost, or Overallocation.

  • Peak Units is useful for simultaneous assignment demand.
  • Work is useful for effort distribution but may hide within-period concurrency when the timescale is too broad.

• Adjusting timescale and zoom: A weekly graph supports portfolio-level scanning, while daily or hourly intervals support precise conflict analysis.

  • The chosen timescale must match the resource calendar and task granularity.

• Worked example: A tester with Max Units = 100% is assigned at 100% to system testing and 50% to defect verification on the same day.

  • Graph demand reaches 150%.
  • The excess is 150% - 100% = 50%.
  • Rescheduling verification, assigning another tester, or adding genuine capacity can remove the peak.

B. Applications and Limitations

The graph communicates allocation patterns efficiently, but detailed corrective work generally requires a tabular or combination view.

• Application: It distinguishes isolated peaks from structural understaffing.

  • Isolated peaks often permit task movement; sustained excess may require hiring, outsourcing, scope change, or deadline revision.

• Application: It supports comparison before and after leveling.

  • Reduced peaks indicate improved feasibility, but shifted finish dates must still be inspected.

• Limitation: The graph may not list all tasks producing a peak.

  • Use Resource Usage or Resource Allocation views to identify the assignments behind the displayed demand.

• Limitation: Aggregation can conceal short overallocations.

  • A daily conflict may disappear in a monthly graph even though the operational schedule remains impossible.

• Management significance: The graph should be treated as an early-warning display, while calendars, assignment details, dependencies, and business priorities provide the evidence required for a final scheduling decision.