A Guide to Resource Scheduling in Project Management

Introduction to Resource Scheduling

Resource scheduling is a critical component of project management that involves planning what resources (people, equipment, materials) are needed to complete project tasks, when they are required, and for how long. Proper resource scheduling helps ensure a project has sufficient resources to progress as planned and allows managers to optimize resource usage across the project lifecycle.

Resource scheduling serves several key purposes:

• Identifies resource requirements for each project task and milestone. This allows managers to understand resource needs at a granular level.
• Prevents resource conflicts and over-allocation. Scheduling reveals where there are insufficient resources to meet task needs and instances where resources are overbooked.
• Enables optimized resource utilization. Scheduling allows managers to track resource utilization across tasks and re-assign resources to avoid bottlenecks.
• Sets project timelines based on resource availability. Project schedules are driven by resource availability since tasks require certain resources to be completed.
• Provides early warning of potential issues. The schedule highlights upcoming resource needs and constraints well in advance so teams can proactively resolve them.
• Improves budgeting accuracy. Knowing detailed resource needs enables more precise budget forecasts.

The resource scheduling process involves assessing the type, quantity, availability, and timing of resources needed. This data is then used to build a resource schedule that is integrated with the overall project schedule. Resource scheduling is an iterative process, requiring continuous refinement as the project progresses and new information emerges. When done effectively, resource scheduling is a best practice that sets projects up for on-time, on-budget delivery.

Identifying Required Resources

The first step in resource scheduling is determining what resources will be required for the project. This involves identifying both the types of resources needed, as well as estimating the quantities.

The project manager should start by reviewing the project scope and deliverables. This will provide insight into the types of work required, such as construction, engineering, software development, etc. The work breakdown structure can help to identify the specific activities and tasks involved.

Some key resource types to consider include:

• Labor - this refers to the human resources needed, and should outline the number of people, roles, skills sets, and effort required. Things like full-time vs part-time resources should be specified.
• Equipment - major equipment, tools, and machinery needed for the work should be identified. This includes both equipment owned by the project as well as any rentals required.
• Materials - consumable materials and supplies to be used by the project need to be determined.
• Facilities - workspace, office space, land, utilities, and other facilities required should be identified.

Once the types of resources are defined, the next step is estimating the quantities needed. Historical data from previous projects can provide initial estimates. Bottom-up estimating looks at the work required for each task to estimate detailed needs. Parametric modeling also uses project characteristics to predict resource needs.

The resource requirements should be outlined in detail in a resource breakdown structure. Good resource planning upfront is crucial for developing an accurate schedule and budget. Care should be taken to identify all necessary resources as missed items can lead to delays and cost overruns down the road.

Resource Breakdown Structure

A resource breakdown structure (RBS) is a hierarchical representation of the required resources for a project. It is an essential tool for effective resource planning and management.

The purpose of an RBS is to break down the resources into categories and types so they can be estimated, scheduled, monitored and controlled more easily.

Some key benefits of developing an RBS include:

• Identifying all resources required for the project upfront during planning. This prevents unexpected resource shortages later.
• Grouping resources into categories so they can be managed efficiently. Common categories are labor, equipment, and materials.
• Providing a consistent structure for resource assignment, capacity planning, cost estimating, and scheduling.
• Enabling what-if analysis related to resource utilization and costs.
• Facilitating resource leveling by understanding priorities and dependencies between resources.

Creating a Resource Breakdown Structure

Follow these steps to create an effective RBS:

• Identify all resource categories for the project. Common categories are human resources, equipment, facilities, and materials.
• Break down each resource category into resource types. For human resources this may include specific teams, roles or skills.
• Decompose each resource type into lower level resources. For labor this could be individual staff members.
• Outline the hierarchy with top-level categories to lower-level individual resources.
• Define each resource with attributes like unit of measure, costs, productive hours, etc.
• Review RBS with project team and subject matter experts. Revise as needed.
• Finalize RBS and incorporate into overall project schedule.

A well-defined RBS allows better scheduling, monitoring and control of resources. It is an essential planning tool for effective resource management in projects.

Resource Calendars

A resource calendar defines when and for how long a specific resource will be available to work on tasks. This allows the project manager to determine realistic task durations based on true resource availability.

Resource calendars are essential for creating an accurate and achievable project schedule. They account for things like:

• Standard working hours and shifts
• Weekends, holidays, and other non-working days
• Vacation time
• Sick time
• Any other factors that limit a resource's availability

Resource calendars should be defined for all major resources, especially those that are only available for a portion of the standard work week or have significant time off planned during the project timeline.

The process involves:

• Identifying the resources that need defined calendars
• Determining working and non-working time for each one
• Setting up the calendars in the scheduling software
• Assigning the appropriate calendar to each resource

This ensures the schedule accounts for resources not being available for task assignments 100% of the time. It prevents setting unrealistic deadlines based on incorrect resource availability assumptions.

Properly defined resource calendars allow the project manager to:

• Produce more accurate task duration estimates
• Identify the true project timeline based on when work can occur
• Avoid over-allocation of resources by scheduling work during their available hours
• Optimize the project plan around resource availability
• Improve resource utilization by working around their off hours

In summary, resource calendars are a critical tool for creating achievable project schedules and plans. They provide the underlying data to determine work hours available for schedule optimization.

Resource Levelling

Resource levelling is an important technique in project management that helps optimize the allocation of resources over the course of a project. It involves reviewing the project schedule to identify overallocations and conflicts in the resource schedule. The goal is to develop an optimal schedule where resource demands do not exceed resource availability constraints.

Resource levelling serves several important purposes:

• Smoothes resource requirements over time to avoid work overloads. This eliminates situations where a resource is assigned too much work at certain times during the schedule.
• Resolves resource conflicts that arise when multiple activities require the same resource at the same time. Levelling balances demands to avoid delays.
• Provides a more realistic schedule baseline by allocating resources evenly over time. This makes it easier to manage the schedule.
• Optimizes utilization of resources so they are working at their capacity without being over-allocated.
• Identifies the critical path to manage priorities and project delays.
• Enables what-if scenario analysis to assess the impacts of changes.

There are two main techniques used for resource levelling:

Resource Limiting - Limits the amount of resources available in specific time periods. Activities may be delayed until sufficient resources are available.

Activity Delaying - Delays activities that require overallocated resources. This pushes them into time periods with lower resource demand.

The basic process for resource levelling includes:

• Identifying overallocations where resource demands exceed capacity.
• Prioritizing activities to level based on critical path status, slack, and priorities.
• Resolving overallocations by limiting resource availability or delaying activities using specialized software or manual techniques.
• Updating the schedule and resolving any issues or conflicts created.
• Iterating as needed until resources are optimally leveled.

Proper resource levelling is key for creating efficient, achievable project schedules. It should be performed regularly throughout the project lifecycle to account for changes and keep resources balanced. With thoughtful levelling, teams can maximize productivity and avoid costly delays.

Resource Optimization

Resource optimization is a key part of effective project scheduling. The goal is to allocate resources in the most efficient way possible to complete project tasks on time and on budget. There are several strategies project managers can use to optimize resource usage:

Avoid Overallocating Resources

Overallocating resources occurs when you assign more work to a resource than they have capacity to handle in the given timeframe. This leads to team members becoming overworked, missing deadlines, and delivering poor quality work. Warning signs of overallocation include team members working excessive overtime, high absenteeism, and tasks consistently not being completed on time.

To avoid overallocation, carefully review the resource utilization rates in your schedule. Identify any resources showing utilization over 80-90% of their available hours. Then redistribute some of their assigned work to other team members with availability. You can also bring on additional temporary resources to handle peak demand periods.

Avoid Underallocating Resources

Underallocation happens when resources are not utilized enough or given sufficient work. This leads to inefficiencies, because their time is not being leveraged effectively. Underutilized team members can also become disengaged over time.

Review your resource usage rates to identify anyone showing low utilization, such as below 50% of their available hours. See if you can consolidate their work and assign them additional tasks to better occupy their time. You may also find opportunities to loan out underutilized resources to other projects that need help.

Level Out Resource Workloads

Look for opportunities to smooth out resource usage peaks and valleys. Try shifting tasks around to avoid overloading resources in certain time periods. You can also look for dependencies that allow starting some work earlier to flatten out resource demands. The goal is to create an even, sustainable workload rather than significant fluctuations week to week.

Resource Pooling

With resource pooling, resources are shared between multiple projects rather than dedicated to a single project. This allows better utilization of resources by sharing them when needed. The key is to create a centralized view of resource availability and demands across all projects. Then you can prioritize and allocate resources based on organizational priorities rather than a single project view.

Automated Resource Optimization Tools

Various software tools can help automate resource optimization. These perform tasks like identifying overallocations, smoothing resource usage, and suggesting alternative resource assignments. While useful, the results should always be reviewed by a project manager to make sure they align with actual resource availabilities and project needs.

With careful planning and some optimization techniques, you can develop an optimal resource schedule that sets your project up for success. The goal is having the right resources available at the right time to keep your project moving forward efficiently.

Scheduling Dependencies

A key aspect of resource scheduling is identifying the dependencies between tasks. This allows you to sequence tasks in the most efficient order. Certain tasks cannot start until other tasks are completed. These are called predecessor tasks.

To properly schedule resources, each task should have defined predecessors if dependencies exist. This connects the tasks in a logical order so that resources are available when needed. Some common types of predecessors are:

• Finish-to-Start (FS) - The predecessor task must finish before the dependent task can start. This is the most common.
• Finish-to-Finish (FF) - The predecessor task must finish before the dependent task can finish.
• Start-to-Start (SS) - The predecessor task must start before the dependent task can start.
• Start-to-Finish (SF) - The predecessor task must start before the dependent task can finish.

Defining these predecessors creates a sequence that determines when tasks can be scheduled based on resource availability. Software tools like Gantt charts can illustrate these dependencies visually. However, manually sequencing tasks by predecessor relationships ensures resources are allocated appropriately before constructing the schedule.

Identifying these connections is crucial for optimizing the project schedule. It prevents bottlenecks where certain tasks can't start on time due to incomplete predecessors. Scheduling dependencies create an orderly workflow so resources can progress efficiently through the project.

Resource Buffers

A resource buffer is extra time built into the project schedule to allow for potential delays or problems related to resource usage. Adding buffers helps ensure that resources are available when needed, avoiding project delays if tasks take longer than expected.

The main purposes of resource buffers are:

• To account for estimation errors or variability in the duration of resource-dependent tasks. No estimate is perfect, so buffers provide wiggle room.
• To absorb minor disruptions or delays without impacting the overall project timeline. This protects the critical path.
• To reduce schedule risk related to resource conflicts, bottlenecks, or over-allocation. Buffers help maintain float.

Determining Optimal Buffer Sizes

The size of each resource buffer should be based on:

• The criticality of the resource - more important or constrained resources may need larger buffers.
• The estimated duration accuracy - longer or more complex tasks warrant bigger buffers.
• Resource contention - heavily used resources prone to conflicts justify more padding.
• Historical data - use past projects to estimate needed buffer sizes.

As a rule of thumb, buffers of 20-50% of the task duration are common. But conduct risk analysis to tailor buffer sizes appropriately.

Buffer Insertion Techniques

Resource buffers can be implemented using various schedule techniques, including:

• Lag time - adding lead or lag time between dependent tasks.
• Duration estimates - increasing estimated durations.
• Resource leveling - using preprocessing leveling delays.
• Splitting tasks - dividing into smaller pieces with buffers between each.
• Separate buffer tasks - adding distinct buffer activities to the schedule.

The specific approach will depend on the scheduling methodology and tool being used. Maintain buffers proactively, monitoring and adjusting them as needed throughout the project lifecycle.

Monitoring Resource Usage

Effectively monitoring resource usage is critical for identifying potential issues and keeping projects on track. Project managers should regularly track if resources are being used as planned and allocated.

Track resource usage

• Review timesheets, project management software, and other tracking tools to compare actual vs planned resource allocation. This allows you to identify if resources are under or overutilized.
• Audit projects to determine if assigned resources are being used effectively or if some are underworked while others are over allocated.
• Watch for resources burning out from overwork or disengaging from being underutilized.

Adjust schedules

• If resources are overallocated, you may need to bring in additional resources or push out some task deadlines.
• For underutilized resources, identify if they can be shifted to other projects or engage them with more work.
• Update resource allocation plans and project schedules accordingly.

Manage changes

• When projects change scope or new priorities emerge, assess the impact on resource scheduling.
• Proactively reallocate resources as needs shift rather than reacting at the last minute.
• Look for opportunities to smooth resource usage and avoid burning out your best resources.
• Keep stakeholders informed of any resource or schedule changes.

Regularly monitoring resource usage against plans allows project managers to identify potential problems early and make adjustments to keep projects and resources on track. This process is key for optimizing resource allocation and maintaining project momentum.

Improving Future Estimates

One of the key ways project managers can enhance future resource scheduling is by analyzing past resource performance and applying lessons learned. This allows you to build up an organizational knowledge base that can feed into progressively better estimates over time.

Some techniques for improving future estimates through past performance analysis include:

• Review resource utilization reports from previous projects to understand where estimates deviated from actuals. Look at both hourly/daily trends as well as overall totals.
• Identify patterns where certain resource types were consistently over or under-allocated. Adjust your base assumptions for future estimates accordingly.
• Document lessons learned throughout each project phase to capture why estimates were off. Was it due to unexpected risks, faulty initial assumptions, or poor task definition?
• Maintain a master lessons learned register that compiles insights from all projects. Tap into this knowledge base when creating estimates.
• Conduct post project reviews with both PM team and resources themselves to understand gaps between planned and actual work. Adjust estimates to account for feedback.
• Analyze trends in resource productivity to determine if output is improving, declining, or variable. Incorporate findings into future planning.
• Leverage historic actuals to create probability distributions and ranges rather than point estimates. Build in buffers based on past variance.
• Enhance skills in cost and schedule estimating through training, standards, and peer reviews. Estimating is a skill that can be continuously developed.

By regularly analyzing past resource performance and applying findings to future estimates, project managers can significantly improve the accuracy and reliability of their resource schedules over time. The key is to constantly inspect, adapt and learn from previous estimating performance.

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