How does the project start date affect the schedule?
How do task links affect the schedule?
How do constraints on tasks affect the schedule?
How do task types affect the schedule? How does effort-driven scheduling affect the schedule? How do manual and automatic scheduling affect the schedule?
How does float (or slack) affect the schedule?
How do deadline dates affect the schedule?
How do calendars affect the schedule?
How do resource assignments drive the schedule?
Yet more technical information about how Project schedules When
you add a new task to a schedule, it automatically is scheduled to start on the project’s start date. As tasks are added to the schedule and connected to other tasks, the start times of tasks will change, and the last task to finish determines the project’s finish date. To find the Project start date or to change it to another date, click Project, and then click Project Information. Of course, there are going to be exceptions. For example, tasks don’t move around as other tasks move. Read below in this article to learn more about manually versus automatically scheduled task scheduling. When you create a new project, you first enter the project's start date. When you schedule a project from the start time, all tasks start at the project start date unless you specify otherwise. For both manually scheduled tasks and automatically scheduled tasks, with no task dependencies or constraints applied, the project's duration is the same as the duration of the longest task. In other words, the project finish date is the same as the longest task's finish date. Task dependencies, such as the finish-to-start dependency between the first and second tasks (as shown here), can change the project's finish date. Nearly all projects should be scheduled from a known start time. Even if you know the date that a project must be completed, scheduling from a start date gives you maximum flexibility. However, you might want to schedule from a finish date when:
As you work with your project that is scheduled from a finish date, be aware of differences in the way that Project handles some actions:
Top of Page How do task links affect the schedule?Task links (dependencies) show the relationship in time of one task to another. Linking tasks creates task dependencies. The long chain of tasks determines the entire length and end of a project. Project management tip As you link tasks in a project, a critical path of links is set up. This critical path determines the end of your project. Learn more about the critical path.
Note about manually scheduled tasks When you link a manually scheduled task to another task, Project respects the link type and places the manually scheduled task relative to the other task. For example, the successor task with a finish-to-start link is shown as beginning when the predecessor finishes. However, the successor task will only move when the link is created. If the predecessor later changes its finish date, the successor’s start date will remain unchanged. However, you can configure Project so that a manually scheduled task does not move when it is linked to another task.
Top of Page How do constraints on tasks affect the schedule?Constraints allow you to control the start or finish date of an automatically-scheduled task. There are three types of constraints:
Project management tip In nearly all cases, use the ASAP constraint. This gives the scheduling engine the most flexibility in determining the ideal finish date for your project. Here are two ways to instantly view the constraints on your tasks.
Constraints with moderate scheduling flexibility will restrict a task from starting or finishing before or after a date you choose. For example, a task with a Start No Earlier Than (SNET) constraint for June 15 and a finish-to-start dependency to another task can begin June 15 if its predecessor is finished by June 15 (or later if its predecessor finishes after June 15), but it can't be scheduled before June 15. For example, this might be appropriate use of constraints if you have a building permit that is only good for a specific dates. In this case, the SNET or FNLT constraints might be used.
With the default finish-to-start task relationship and an ASAP constraint applied to these tasks, the successor task (the second one) is scheduled to begin as soon as the predecessor task (the first one) is scheduled to finish. With a SNET constraint applied, the successor task cannot begin before the constraint date, even if (as shown here) the predecessor task is completed before the constraint date. The following table lists the constraints provided in Project.
By default, all tasks in a project that is scheduled from the start date have the ASAP constraint applied. Likewise, by default, all tasks in a project that is scheduled from the finish date have the As Late As Possible (ALAP) constraint applied. Inflexible constraints usually override any task dependencies and restrict a task to a date you choose. For example, a task with a Must Start On (MSO) constraint for September 30 and a finish-to-start dependency to another task will always be scheduled for September 30 no matter whether its predecessor finishes early or late. You can change this behavior. Click File, click Options, click Schedule, then select the Tasks will always honor their constraint dates check box. Top of Page How do task types affect the schedule?Task types apply only to automatically-scheduled tasks, and come in three flavors: fixed units, fixed work, and fixed duration. Project looks at a task’s type to determine how duration, work, and units will behave as Project schedules your project. Each of the task types affects scheduling when you edit one of the three elements as follows.
Some examplesLet's say you have a fixed-units task, with 1 full-time resource unit available for 8 hours each day. You set the task up with a 10-day duration and 80 hours of work.
Now let's say you make the same task a fixed-work task. This means that the task can take only the amount of work that you specify: no more, no less. In this example, the task has 1 full-time resource available for 8 hours each day, and it has a 10-day duration with 80 hours of work.
Finally, let's say you make the same task a fixed-duration task. This means that the task must be completed in the duration that you specify. Again, in this example, the task has 1 full-time resource available for 8 hours each day, and it has a 10-day duration with 80 hours of work.
If you find out that the task will take 20 hours of additional work, Project recalculates the task's resource units, so that the additional work can still be completed within the 10-day duration. The task now has 100 hours of work, with a duration of 10 days and 1.25 resource units. The resource unit that is currently assigned to the task is allocated at 125%. You need to assign another resource to account for the additional 25% allocation. Note: Because assignments of cost resources don't have values for work or units, these values will not be recalculated when the task's start date or finish date is modified. Dates also are never recalculated for a cost resource assignment, because you cannot modify the work or units. Here’s a table of things to keep in mind about task types.
Top of Page How does effort-driven scheduling affect the schedule?For all tasks, after you assign a resource, the task is scheduled according to this formula (assuming tasks are the default fixed-units task type): Duration = Work / Units For any task, you can choose which piece of the equation Project calculates by setting the task type. When you assign or remove people from a task, Project lengthens or shortens the duration of the task based on the number of resources that are assigned to it, but Project does not change the total work for the task. This is called effort-driven scheduling. This setting is usually turned off. To turn it on, click File, click Options, click Schedule, then select the New tasks are effort-driven check box. Although effort-driven scheduling can work in most scenarios, you may want to change this behavior to more accurately reflect what happens on a particular task when resources are added or removed. For example, you may want to see the total work increase as you add more people to a particular task.
Note: You cannot remove effort-driven scheduling from fixed work tasks. Fixed work tasks do not have flexible work values, and are therefore always effort-driven. When you work with effort-driven scheduling, keep the following in mind:
Top of Page How do manual and automatic scheduling affect the schedule?Knowing the differences between manually scheduled tasks and automatically scheduled tasks is key to understanding how Project schedules your project. Generally, manually scheduled tasks put you in control of the schedule. When you add a task to your schedule, it stays put. However, this isn’t always the best way to design a schedule, especially as projects get more complicated, where you might want to use automatically-scheduled tasks in order to take advantage of Project’s powerful scheduling engine. Take a look at the picture below. It shows the two different types of tasks, the first two manually scheduled, and the last two automatic.
Note that for the manually scheduled tasks, the duration is a text value as well as a number. Since the duration can be a text value, a start date hasn't been set automatically by Project, and the Gantt bar is only partially displayed to reflect the uncertainty of the task schedule at this point. For the automatically-scheduled task, the duration is a number value with a time unit appended, such as “12h” for twelve hours duration. By definition, automatically-scheduled tasks with valid durations, start dates, and finish dates—and therefore, bars—are automatically drawn by Project. Now, it gets a little tricky sometimes with the information you provide for manually scheduled tasks. All that is needed for Project to draw bars on a manually scheduled task are three time values: duration, start date, and finish date. If you set two of these values for a manually scheduled task, the third value will be calculated by Project automatically, and the task will remain manually-scheduled. So look out for this kind of “unexpected” behavior from Project. Note: Tasks are manually scheduled by default. Project managers who are accustomed to automatic scheduling with past versions of Project can turn the manual scheduling feature off for specific tasks or for the entire project. Some projects, especially complicated ones, may require Project's powerful scheduling engine to take care of scheduling for you. To change all tasks to be automatically scheduled, click New Tasks: Automatically Schedule at the bottom of the Project application window. Manually scheduled tasksYou can place a manually scheduled task anywhere in your schedule, and Project won't move it. This new feature gives you greater flexibility and control over planning and managing the schedule. Why would you care? Well, at times project schedules are often very informal. They begin as simple lists of dates from e-mails, meeting with stakeholders, or a hallway conversation. Project managers very often do not have complete information on work items. For example, they may only be aware of when a task needs to be started, but not its duration until they have an estimate from their team members. Also, they may know how long a task will take, but they do not know it can be started until they have approval from the resource manager. Here are some things to keep in mind with manually scheduled tasks.
The following table shows how Project attributes are defined and used for scheduling manually and automatically scheduled tasks.
Automatically scheduled tasksAutomatically scheduled tasks are the classic way Project schedules your tasks. Automatic scheduling provides a highly structured, systematic means of managing project schedules. Based on users’ input, such as task duration, planned work, number of resources, and constraint dates, Project calculates the earliest and latest dates for tasks for the optimal schedule. Project schedules a project from the information that you enter about the following:
If anything about your project changes after you create your schedule, you can update the tasks or resources and Project adjusts the schedule for you. For each task, you might enter one or all of the following:
Using this information, Project calculates the start date and finish date for each task. You can enter resources in your project and then assign them to tasks to indicate which resource is responsible for completing each assignment. Not only does this help you plan project staffing, it can also help you to calculate the number of machines needed or the quantity of material to be consumed. If you enter resources, task schedules are further refined according to the following resource information:
Other elements, such as lead time and lag time for links, task types, resource availability, and the driving resource, can affect scheduling, so understanding the effects of these elements can help you to maintain and adjust your schedule as needed. Note: Project calculates the duration of automatically scheduled tasks based on the definitions of the duration units (Click File, click Options, then click Schedule). Just like a normal monthly calendar, the year begins in January and each week begins on Sunday or Monday. By default, when Project calculates duration units, one day equals 8 hours, one week equals 40 hours, and one month equals 20 working days. If you enter start and finish dates for tasks and don't enter start and finish times, Project uses 8:00 A.M. as the default start time and 5:00 P.M. as the default end time. Changing task scheduling modesYou can change a task's scheduling back and forth from automatic to manual (click File, click Options, then click Schedule). When you change task modes, keep the following in mind.
Top of Page How does float (or slack) affect the schedule?Float (also known as slack) helps you find those tasks that can budge without changing the end date of your project. You may want to view tasks that currently can slip without affecting the critical path (total slack) or those tasks that can slip before affecting the task that they are connected to (free slack). Here are two ways to view float in your schedule.
Here a couple things to keep in mind about float.
Top of Page How do deadline dates affect the schedule?Deadline dates don't usually affect task scheduling. They are used to indicate a target date you don't want to miss, without requiring you to set a task constraint that could affect scheduling if predecessor tasks change. A task with a deadline is scheduled just like any other task, but when a task finishes after its deadline, Project displays a task indicator notifying you that the task missed its deadline. To review or change a task deadline, right-click on the task, click Task Information, then click the Advanced tab. Use the Deadline box. Deadline dates can affect the total slack on tasks. If you enter a deadline date before the end of the task's total slack, total slack will be recalculated by using the deadline date rather than the task's late finish date. The task becomes critical if the total slack reaches zero. You can set deadlines for summary tasks as well as individual tasks. If the summary task's deadline conflicts with any of the subtasks, the deadline indicator signifies a missed deadline among the subtasks. But deadline dates can affect how tasks are scheduled if you set a deadline date on a task with an As Late As Possible (ALAP) constraint. The task is scheduled to finish on the deadline date, though the task could still finish after its deadline if its predecessors slipped. Top of Page How do calendars affect the schedule?Calendars determine the standard working time and non-working time, such as weekends and holidays, for the project. Note: The dates of manually scheduled tasks (if entered) will not change based upon changes to the project or resource calendars. Project calendars are used to determine the resource availability, how resources that are assigned to tasks are scheduled, and how the tasks themselves are scheduled. Project and task calendars are used in scheduling the tasks, and if resources are assigned to tasks, resource calendars are used as well. Calendars override each other’s settings in the following ways.
To work with calendars, click Project, then click Change Working Time.
Top of Page How do resource assignments drive the schedule?If you don't assign resources to tasks in your project, Project calculates the schedule using durations, task dependencies, constraints, and project and task calendar information. If you do assign resources, the tasks are also scheduled according to resources' calendars and assignment units, providing for more accurate scheduling. Note: Manually scheduled tasks are not affected by resource calendars. When a resource is assigned to a manually scheduled task, the scheduling of the task will not change. An assignment is the association of a specific task with a specific resource that is responsible for completing the task. More than one resource can be assigned to a task. Work resources, material resources, and cost resources can be assigned to tasks. Unlike work resources, assigning material resources or cost resources to a task does not affect task scheduling. For example, in your project you have a task named Develop specifications. You also have an engineering resource, Sean. If you assign Sean to the Develop specifications task, the scheduling of this task depends on Sean's resource calendar and assignment units, in addition to task information such as duration, task dependencies, constraints, and calendars. In addition to scheduling according to task information, after you assign resources to the tasks in your project, Project has additional resource and assignment information to use in calculating schedule information, including:
To assign resources to tasks, click the Resource tab, and then click Assign Resources . Top of Page Yet more technical information about how Project schedules
Top of Page These instructions are specific to Microsoft Project 2007. What do you want to learn?
The big picture: How is a project scheduled?Project schedules a project from the information that you enter about the following:
If anything about your project changes after you create your schedule, you can update the tasks or resources and Project adjusts the schedule for you. For each task, you might enter one or all of the following:
Using this information, Project calculates the start date and finish date for each task. You can enter resources in your project and then assign them to tasks to indicate which resource is responsible for completing each assignment. Not only does this help you plan project staffing, it can also help you to calculate the number of machines needed or the quantity of material to be consumed. If you enter resources, task schedules are further refined according to the following resource information:
Other elements, such as lead time and lag time, task types, resource availability, and the driving resource, can affect scheduling, so understanding the effects of these elements can help you to maintain and adjust your schedule as needed. Top of Page How does the project start date affect the schedule?If you enter a start date for the project, by default, Project schedules tasks to begin on the project's start date and calculates the project's finish date based on the last task to finish. As you enter more information about tasks, such as task dependencies, durations, and constraints, Project adjusts the schedule to reflect more accurate dates for tasks.
When you create a new project, you first enter the project's start date. When you schedule a project from the start date, all tasks start at the project start date unless you specify otherwise. With no task dependencies or constraints applied, the project's duration is the same as the duration of the longest task. In other words, the project finish date is the same as the longest task's finish date. Task dependencies, such as the finish-to-start dependency between the first and second tasks (as shown here), can change the project's finish date. Nearly all projects should be scheduled from a known start date. Even if you know the date that a project must be completed, scheduling from a start date gives you the maximum flexibility. However, you might want to schedule from a finish date when:
As you work with your project that is scheduled from a finish date, be aware of differences in the way that Project handles some actions:
Top of Page What are the default settings for calculating the schedule?Project calculates the duration of tasks based on the definitions of the duration units on the Calendar tab of the Options dialog box (Tools menu). Just like a normal monthly calendar, the year begins in January and each week begins on Sunday or Monday. By default, when Project calculates duration units, one day equals 8 hours, one week equals 40 hours, and one month equals 20 working days. If you enter start and finish dates for tasks and don't enter start and finish times, Project uses 8:00 A.M. as the default start time and 5:00 P.M. as the default end time. Top of Page How do constraints affect the schedule?When you need to control the start or finish date of a task, you can change the constraint on the task. Flexible constraints work with task dependencies to make a task occur as soon or as late as the task dependency will allow. For example, a task with an As Soon As Possible (ASAP) constraint and a finish-to-start dependency will be scheduled as soon as the predecessor task finishes. By default, all tasks in a project that is scheduled from the start date have the ASAP constraint applied. Likewise, by default, all tasks in a project that is scheduled from the finish date have the As Late As Possible (ALAP) constraint applied. Constraints with moderate scheduling flexibility will restrict a task from starting or finishing before or after a date you choose. For example, a task with a Start No Earlier Than (SNET) constraint for June 15 and a finish-to-start dependency to another task can begin June 15 if its predecessor is finished by June 15 (or later if its predecessor finishes after June 15), but it can't be scheduled before June 15.
With the default finish-to-start task relationship and an ASAP constraint applied to these tasks, the successor task (the second one) is scheduled to begin as soon as the predecessor task (the first one) is scheduled to finish. With a SNET constraint applied, the successor task cannot begin before the constraint date, even if (as shown here) the predecessor task is completed before the constraint date. Inflexible constraints override any task dependencies by default and restrict a task to a date you choose. For example, a task with a Must Start On (MSO) constraint for September 30 and a finish-to-start dependency to another task will always be scheduled for September 30 no matter whether its predecessor finishes early or late. If a task that is constrained to a date has a predecessor that finishes too late for the successor to begin on the date specified in the constraint, negative slack can occur. To review or change the constraint on a task, select the task, click Task Information , and then click the Advanced tab. Constraint information is in the Constraint type and Constraint date boxes.Top of Page How do deadline dates affect the schedule?Deadline dates don't usually affect task scheduling. They are used to indicate a target date you don't want to miss, without requiring you to set a task constraint that could affect scheduling if predecessor tasks change. A task with a deadline is scheduled just like any other task, but when a task finishes after its deadline, Project displays a task indicator notifying you that the task missed its deadline. Deadline dates can affect the total slack on tasks. If you enter a deadline date before the end of the task's total slack, total slack will be recalculated by using the deadline date rather than the task's late finish date. The task becomes critical if the total slack reaches zero. You can set deadlines for summary tasks as well as individual tasks. If the summary task's deadline conflicts with any of the subtasks, the deadline indicator signifies a missed deadline among the subtasks. But deadline dates can affect how tasks are scheduled if you set a deadline date on a task with an As Late As Possible (ALAP) constraint. The task is scheduled to finish on the deadline date, though the task could still finish after its deadline if its predecessors slipped. To review or change a task deadline, select the task, click Task Information , and then click the Advanced tab. Use the Deadline box.Top of Page How do calendars affect the schedule?Calendars determine the standard working time and nonworking time, such as weekends and holidays, for the project. They are used to determine the resource availability, how resources that are assigned to tasks are scheduled, and how the tasks themselves are scheduled. Project and task calendars are used in scheduling the tasks, and if resources are assigned to tasks, resource calendars are used as well. The calendars referred to in Project are:
To work with calendars, on the Tools menu, click Change Working Time. Top of Page How do resource assignments drive the schedule?If you don't assign resources to tasks in your project, Project calculates the schedule using durations, task dependencies, constraints, and project and task calendar information. If you do assign resources, the tasks are also scheduled according to resources' calendars and assignment units, providing for more accurate scheduling. An assignment is the association of a specific task with a specific resource that is responsible for completing the task. More than one resource can be assigned to a task. Work resources, material resources, and cost resources can be assigned to tasks. Unlike work resources, assigning material resources or cost resources to a task does not affect task scheduling. For example, in your project you have a task named Develop specifications. You also have an engineering resource, Sean. If you assign Sean to the Develop specifications task, the scheduling of this task depends on Sean's resource calendar and assignment units, in addition to task information such as duration, task dependencies, constraints, and calendars. In addition to scheduling according to task information, after you assign resources to the tasks in your project, Project has resource and assignment information to use in calculating schedule information, including:
To assign resources to tasks, click Assign Resources . Top of Page What information can help me analyze my project's progress?Five pieces of task information help you analyze progress as you track tasks in your project: duration, work, start date, finish date, and cost. Variations of each of these types of fields help you compare and evaluate your progress: planned, scheduled, actual, and remaining. For example, for one task, there can be fields of information containing planned work, scheduled work, actual work, and remaining work. The contents of these fields might match one another, or they might all be different. Variances between certain fields can also be examined for useful tracking information. For this reason, these fields are referred to as tracking fields.
Top of Page What do we call the schedule that shows when to start and finished the project?A project schedule indicates what needs to be done, which resources must be utilized, and when the project is due. It's a timetable that outlines start and end dates and milestones that must be met for the project to be completed on time.
What is the project schedule process?The project schedule is detailed enough to show each task to be performed, the resource allocated to perform the task, the start and end date of each task and the duration in which the task will be performed. During the lifecycle of a project, the project progress is monitored by the project schedule.
What are the three main types of schedule in project management?What are the three types of project schedule?. A master schedule.. A milestone schedule.. A detailed schedule.. What is planning and scheduling in project management?The process of planning primarily deals with selecting the appropriate policies and procedures in order to achieve the objectives of the project. Scheduling converts the project action plans for scope, time cost and quality into an operating timetable.
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