Assigning resources to your project tasks

Applies to
Microsoft Office Project 2003

Once you have decided what needs to be done to complete your project, you'll want to decide who will do the work (work: For tasks, the total labor required to complete a task. For assignments, the amount of work to which a resource is assigned. For resources, the total amount of work to which a resource is assigned for all tasks. Work is different from task duration.).

Project provides easy ways to assign the right people to tasks, as well as the necessary equipment, and even the materials to be used.

What are assignments?

Why should I assign resources to tasks?

How do I assign resources to tasks?

What is a proposed assignment?

How do I adjust work resource assignments?

How do I adjust material resource assignments?

What are work contours?

How do assignments affect scheduling?

What is work and how does it affect the schedule?

What is effort-driven scheduling?

How do I adjust resource assignments automatically?

What are assignments?

Assignments are the associations between specific tasks and the resources needed to complete them. More than one resource can be assigned to a task. Both work resources (work resource: People and equipment resources that perform work to accomplish a task. Work resources consume time [hours or days] to accomplish tasks.) and material resources (material resources: Consumable materials or supplies, such as concrete, wood, or nails.) can be assigned to tasks.

Assign resources to tasks in your project to indicate who or what is needed to complete the tasks in your schedule. Once assignments are made, the tasks are scheduled according to resource calendars (resource calendar: A calendar that specifies working and nonworking time for an individual resource. A resource calendar differs from a base calendar, which specifies working and nonworking time for more than one resource.) and assignment units (assignment units: The percentage of a work resource's time, or units, that the resource is assigned to a task.), which provides for more accurate scheduling.

Why should I assign resources to tasks?

Specifically, assign resources to tasks in your project when your goal is to:

  • Track the amount of work done by people and equipment, or the amount of material used, in the completion of tasks.
  • Ensure high accountability and understanding of the project. When responsibilities are clear, there is less risk that tasks will be overlooked.
  • Be more accurate in scheduling how long tasks will take and when they are likely to be completed.
  • Monitor resources with too little or too much work assigned.
  • Account for resource time and costs.

How do I assign resources to tasks?

You assign resources by selecting the task, selecting the resource from (or adding the resource to) the resource list, and entering the assignment units.

For work resources, the default value for assignment units is the same as the maximum units (maximum units: The maximum percentage or number of units that a resource is available to be scheduled for any tasks. The maximum units value indicates the highest capacity at which the resource is available for work; the default value is 100 percent.) value, but not exceeding 100 percent. A units value of 100% indicates that the resource is assigned full time on the task, based on the available working time specified in the resource calendar. For material resources, the default assignment units value is 1. A units value of 1 represents one of the unit of measurement, or label, you set up for the material resource (for example, 1 ton or 1 cubic yard).

By default, the names of assigned resources appear with the task's Gantt bars (Gantt bar: A graphical element on the chart portion of the Gantt Chart view representing the duration of a task.).

You can review detailed assignment information in the Task Usage view or Resource Usage view. In the Task Usage view, the names of the assigned resources are grouped under each task name. In the Resource Usage view, the names of the assigned tasks are grouped under each resource name. These two views appear as a table and a timesheet showing the distribution of work by time period.

What is a proposed assignment?

By specifying a booking type for resources in Project, resources can be marked as committed or proposed. You may want to set a resource's booking type to proposed in the planning stages of your project. It means that you reserve the resource to work on tasks for the time being. When you assign a proposed resource to a task, the assignment will be flagged as a proposed assignment. Only assignments made to committed resources are true assignments.

How do I adjust work resource assignments?

You can adjust the time a work resource spends on a task by adjusting units (units: The quantity of a resource assigned to a task. The maximum units is the maximum number of units available for the resource. For example, if you have three plumbers, the maximum units is 300 percent or three plumbers working full-time.), work (work: For tasks, the total labor required to complete a task. For assignments, the amount of work to which a resource is assigned. For resources, the total amount of work to which a resource is assigned for all tasks. Work is different from task duration.), contours (contour: The shape of how scheduled work for an assignment is distributed across time. Use a contour to control how Project schedules the work of a resource. Contour examples include flat, back-loaded, front-loaded, bell, turtle, and more.), or assignment start and finish dates.

When you first assign a resource to a task, you establish the assignment units. For a work resource, the units indicate the percentage of available working time, based on the resource calendar, that this resource will devote to this task. Full time is typically 100 percent, meaning that this is a full-time resource working full time on this task. If a part-time resource with 25 percent maximum units is assigned, for example, the default assignment units value is 25%. You can also assign a full-time resource part time on an assignment. For example, you can assign the full-time resource to work 50 percent on one task and 50 percent on another. If a resource calendar is set for 8 hours of working time for Thursday, and the resource is scheduled 100 percent on a task for Thursday, the resource works 8 hours on Thursday. However, if the resource calendar is set for 4 hours on Friday, and if the resource is scheduled 100 percent on a task for Friday, the resource works 4 hours on Friday.

When you assign a work resource to a task, work is immediately calculated for the assignment. The way work is calculated depends on the task type (task type: A characterization of a task based on which aspect of the task is fixed and which aspects are variable. There are three task types: Fixed Units, Fixed Work, and Fixed Duration. The default task type in Project is Fixed Units.) (fixed units, fixed duration, or fixed work). For example, when a resource is first assigned to a fixed-unit task (fixed-unit task: A task in which the assigned units [or resources] is a fixed value and any changes to the amount of work or the task's duration do not affect the task's units. This is calculated as follows: Duration x Units = Work.), the amount of assigned work depends on the task duration (duration: The total span of active working time that is required to complete a task. This is generally the amount of working time from the start to finish of a task, as defined by the project and resource calendar.). You can change the total work value for an assignment when you want to decrease the amount of time a resource spends on a task or when you want to shift work from one assigned resource to another. Changing the total work value can be helpful when you're trying to shorten the schedule or when you're trying to even out the workload of overallocated (overallocation: The result of assigning more tasks to a resource than the resource can accomplish in the working time available.) or underallocated (underallocation: Assigning a resource to work fewer hours than the resource has available.) resources.

In addition to changing the amount of total work on an assignment, you can contour the work, that is, adjust how much of the total work is done across the span of the assignment. With preset contours, you can ramp up, ramp down, ramp up and then down, and more. The total work for an assignment with a contour applied is divided over the task duration, according to the contour you choose. You can also create your own work contour.

If an assignment's start and finish dates are different from the task's start or finish dates, you can adjust them in the Assignment Information dialog box.

How do I adjust material resource assignments?

You can adjust the material usage and consumption rate of material resource assignments by adjusting work and units. You can also contour material usage and set assignment start and finish dates.

When you first assign a resource to a task, you establish the assignment units. For material resources, units are considered the amount or rate of material consumption. The units you assign for material resources indicate the quantity of the material to be consumed in the completion of the task using the unit of measurement, or label, you enter for the material resource (for example, 20 tons or 5 cubic yards).

If the material resource has variable material consumption (variable material consumption: The time-based quantity of material resource to be used in an assignment. A variable consumption indicates that the amount of material that is used changes if the task duration or assignment length changes.), you indicate the rate in the Units field. For example, if 10 tons of steel will be used each week on this assignment, enter 10/week as the assignment units. However, if the resource has fixed material consumption (fixed material consumption: Absolute quantity of a material resource to be used to complete an assignment. A fixed consumption rate indicates that the amount of material used will be constant, regardless of changes to task duration or assignment length.), simply enter the total quantity of material to be used, without a time label. For example, if 40 yards of soil will be used for the assignment whether the task duration increases or decreases, enter 40.

When you assign a material resource to a task, work is immediately calculated for the assignment. For materials, work is considered to be the total material usage. The way the total material usage is calculated depends on whether the resource's consumption is designated as fixed or variable. If its consumption is fixed, the total material usage is equal to the units value. For example, if the assignment units value on a task is 20 boxes, the work is also 20 boxes. However, if the resource's consumption is variable, the total material usage indicates the total amount of material to be used throughout the duration of the task. For example, if the assignment units value on the task is 20 boxes/day, and the task duration is 4 days, the work value is 80 boxes.

In addition to changing the amount of total work (material usage) on an assignment, you can contour the material usage; that is, you can adjust how much of the total material is to be used over the course of the assignment. You can use preset contours to ramp up, ramp down, ramp up and then down, and more. The total material usage for the assignment is divided over the task duration, according to the contour you choose. You can also create your own work contour. If the material resource assignment start and finish dates are different from the task start or finish dates, you can adjust them in the Assignment Information dialog box.

What are work contours?

When an assignment is first made, it has a flat work contour by default. A flat work contour means that the work for the assignment is spread out evenly over the length of the assignment.

However, if you want to distribute the total work (time, for work resource, or stock, for material resources) in a different way, you can choose one of the following work contours, available in the Assignment Information dialog box:

  • Back loaded
  • Front loaded
  • Double peak
  • Early peak
  • Late peak
  • Bell
  • Turtle

These contours indicate the shapes that the work distribution takes over the assignment span. The way the contours apply depends on the task type (fixed units, fixed duration, or fixed work).

You can view work contours in the timesheet portion of the Task Usage or Resource Usage view. A work contour indicator will appear in the table portion of the Task Usage or Resource Usage view.

If none of the preset contours meet your needs, you can create your own contour by manually adjusting the work amounts in the timesheet portion of the Task Usage or Resource Usage view. However, be careful to account for the total work value across the assignment span. It's easy to accidentally add or remove work when making manual adjustments in a usage view, which might inadvertently change the total work value (shown in the Work field in the table portion of the usage view).

How do assignments affect scheduling?

If you don't assign resources to tasks in your project, Project calculates the schedule using only task duration, task dependency, constraints, and project and task calendar (task calendar: The base calendar that you can apply to individual tasks to control their scheduling, usually independent of the project calendar or any assigned resources' calendars. By default, all tasks use the project calendar.) information. If you do assign resources, the tasks are also scheduled according to the resources' calendars and assignment units, which provides for more accurate scheduling.

Unlike work resources, assigning material resources to a task does not affect task scheduling. However, editing material assignments can affect task scheduling if only material resources (and not work resources) are assigned to a task. In this case, changing the work of an assignment with variable material consumption can change the task duration. For example, suppose you have a material resource with assignment units of 10 tons/hour, and the duration is 8 hours. If you change the units to 20 tons/hour, the task duration changes to 16 hours.

In addition to scheduling according to task information, after you assign resources to the tasks in your project, Project uses resource and assignment information to calculate schedule information, including:

For all tasks, after you assign a resource, the task is scheduled according to the formula Duration = Work / Units. The following table shows how each of the task types affects scheduling when you edit one of the three elements.

In a If you revise work If you revise duration If you revise units
Fixed-units task Duration is recalculated Work is recalculated Duration is recalculated
Fixed-work task Duration is recalculated Units are recalculated Duration is recalculated

What is work and how does it affect the schedule?

Work is the labor, time (in terms of minutes, hours, days, or weeks for work resources), or quantity (for material resources) required to complete a task or assignment.

Work is different from task duration. For example, a resource may require 32 hours of work to complete a task, but the task may be scheduled with a duration of 2 days. In this case, more than one resource needs to be assigned to this task. Working 8 hours a day on the task, two people would complete the task in 2 days.

As soon as you assign a work resource to a task, work is calculated for the assignment. The way work is calculated depends on whether the task is effort-driven. For example, if you have an effort-driven task with a 4-day duration and you assign two resources to it, each resource is assigned to 16 hours of work. On the other hand, if you have a non-effort-driven task with a 4-day duration and you assign two resources to it, both resources are assigned to 32 hours of work.

Work can be viewed as timephased (timephased: Task, resource, or assignment information that is distributed over time. You can review timephased information in any available time period in the fields on the right side of the Task Usage and Resource Usage views.) data in the Task Usage and Resource Usage views. In the timesheet portion of these views, the work is shown spread across the time period. You can contour this work in different shapes, such as a front-loaded, back-loaded, or bell shape.

You can also fine-tune the work for each time period yourself by manually editing the work amounts in the timesheet portion of the Task Usage or Resource Usage view. However, be careful to account for the total work value across the assignment span. It's easy to add or remove work when making manual adjustments in a usage view, which might inadvertently change the total work value (shown in the Work field in the table portion of the usage view).

What is effort-driven scheduling?

Assigning resources to tasks affects the schedule differently if the tasks are effort-driven.

Effort-driven scheduling means that as you add resources to a task assignment, work is redistributed among all the resources to maintain the same amount of work overall. Likewise, if you remove resources from an effort-driven task, work is redistributed among the remaining resources—again, to maintain the same amount of work overall.

By default, tasks have fixed units and are effort-driven. This means that as more resources are assigned to a task, there is less work each resource needs to do. Because it's a fixed-unit task, adding resources also reduces duration.

If you have a fixed-duration, effort-driven task, the more resources you assign, the fewer units the resources need to complete the reduced amount of work for the assignment.

By its nature, a fixed-work task is effort-driven. If you add resources, the work is distributed among the assignments, and duration decreases.

How do I adjust resource assignments automatically?

The Resource Substitution Wizard, available only in Project Professional 2003, allows you to optimize your project plans by recommending the best resources for tasks based on their skills, current workload, and availability. The wizard can make skills-based resource recommendations by analyzing resources across an organization or within a department.

The Resource Substitution Wizard provides the following benefits to your projects:

  • Recommended resource assignments are listed for tasks in all the projects you specify.
  • If you choose, the wizard automatically makes the recommended assignment changes.
  • You may be able to shorten your schedule while avoiding overallocations, because resource availability and skills are considered in the recommended assignment changes.
  • You can print a report of the results of the wizard, showing run date, run time, projects, resources, resource freeze horizon, project teams, and other scheduling options.

The Resource Substitution Wizard requires careful planning and configuration. You need to consider the following conditions in order for the wizard to run efficiently and to return the most meaningful results: