What is the difference between schedule and schedule

Scheduling tasks with Project: background information

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How does a project's start date affect its schedule?

When you add a new task to a project schedule, its start is automatically set as the project start date. If more tasks are now added to the schedule and these are linked with other tasks, the start times of the tasks change and the last task to be completed determines the end date of the project.

  • If you want to view or change the start date of the project, click Project, and then click Project information.

Of course there are always exceptions. For example, tasks are not moved in the same way as other tasks. The article below compares manually and automatically scheduled tasks.

When creating a new project, enter the project start date first. When you schedule a project from the start date, all tasks begin at the start time of the project unless you specify a different start time.

For manually scheduled and automatically scheduled tasks with no task dependencies or restrictions applied, the duration of the project is the same as the duration of the longest task. This means that the project finish date is identical to the finish date of the longest task.

Dependencies on processes, e.g. For example, the end-to-start dependency between the first and second task (as shown here) can change the end date of the project.

Most projects should be scheduled based on a known starting time. Even if the date of the project completion is known, planning from the start date offers you maximum flexibility.

However, it may be a good idea to start scheduling from the finish date if:

  • You need to determine when to start a project in order to meet a specific finish date.

  • The exact start date of the project is unknown (for example, if you are dependent on the work of a supplier and delivery may be delayed).

  • You need to plan from the deadline according to your project management methodology.

When working with a project that is scheduled based on the finish date, you need to be aware that some actions are performed differently in Project:

  • When entering an automatically planned activity, its end date is automatically assigned the restriction "As late as possible" (SSWM) in Project. Other restrictions should only be set if necessary (right-click an operation, and then click information).

  • If you change the finish date of an automatically scheduled task by dragging a task bar, the restriction "Finish no later than" (ENSA) is automatically assigned.

  • If you schedule a project that was previously planned from the start date to be based on the finish date, this removes any reconciliation delays and reconciliation interruptions from tasks and assignments that were scheduled automatically. Manually scheduled operations are not affected.

  • If you are using auto-leveling to reduce resource congestion in the project, Project will add the leveling delay after the operation, not before the operation (if you want to review the leveling settings, click the tab resource and then on Capacity leveling).

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How do task links affect the schedule?

Activity links (dependencies) show the temporal relationships between activities. When activities are linked, relationships are created. Long-term task chaining determines the overall length and finish date of a project.

Tip for project managers When you link the tasks of a project, these links are used to create a critical path. This critical path determines the end of the project. You can find more information about the critical path here.

Link type

example

description

End-start (EA)

The dependent task (B) cannot begin until the task on which it depends (A) has been completed.

For example, if you have two tasks, Dig the Foundation and Pour Concrete, the Pour Concrete task cannot begin until the Dig Foundation task is complete.
When you link tasks in Project, the default link type is finish-to-start.
This link type is the standard type. If you do not specify a link type, the finish-start relationship is assumed.

Beginning-beginning (AA)

The dependent task (B) cannot begin until the task on which it depends (A) has started.

The dependent task can begin anytime after the task on which it depends begins. For the AA link type, both processes do not have to start at the same time.

If z. B. the two processes "pour concrete" and "smooth concrete" are available, the process "smooth concrete" can only begin after the process "pour concrete" has started.

End-end (EE)

The dependent task (B) cannot be completed until the task on which it depends (A) is completed.

The dependent operation can be completed at any time after the operation on which it depends has completed. Both processes do not have to be completed at the same time for the EE link type.

For example, the cabling and piping operations must both be completed before acceptance can take place.

Start-end (AE)

The dependent task (B) cannot be completed until the task on which it depends (A) has started.

The dependent task can be completed at any time after the task on which it depends begins. For the AE linkage type, the dependent activity does not have to be completed at the same time as the start of the activity on which it depends.

This type of link is rarely used in project management. An example could be the roofing of a house with the two processes "Covering the roof" and "Monitoring work". In this case, the roofer could start work at any time, but the foreman entrusted with the supervision must show up at some point before the roofing is completed.

Note on manual planned 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 is displayed with a finish-to-start link as the start when the predecessor is finished. However, the successor task is only moved when the link is created. If the predecessor later changes its end date, the successor's start date remains unchanged.

However, you can configure Project so that a manually scheduled task is not moved when it is linked to another task:

  1. click on file, Options and then on scheduling.

  2. Uncheck the box Manually update scheduled tasks when editing links.

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How do task restrictions affect the schedule?

You can use task restrictions to control the start or end date of an automatically scheduled task. There are three types of restrictions:

  • No specific dates are assigned to flexible restrictions. By setting these constraints, tasks can start as early as possible or as late as possible, with the task ending before the project ends, taking into account other constraints and relationships in the schedule.

  • Semi-flexible restrictions must be assigned a date that controls the earliest or latest start or finish date for a task. With these restrictions, a process can be ended at any time, provided that the start or end time is met.

  • Fixed restrictions must be assigned a date that controls the start or finish date of the task. These constraints are useful when the schedule needs to take into account external factors, such as: B. the availability of material or resources, deadlines, contract milestones and start and end dates.

Tip for project managers In almost all cases it is advisable to work with the SFWM restriction (as early as possible). This gives the planning module the highest level of flexibility for determining the ideal end date for the project.

The following are the two methods to view all operation restrictions immediately:

  • To review or change the restriction for an operation, right-click the operation and then click in the dialog box Information about the process on the tab Extended. Limitation information is in the fields Restriction type and Restriction date contain.

  • If any type of constraint other than SFWM or SSWM (as late as possible) is used, the type of constraint is marked with the appropriate symbol in the "Indicators" column in every table view, such as the Gantt chart.

Restrictions with moderate flexibility in scheduling restrict starting or stopping a task before or after a date you specify. For example, a task with a start no earlier than (SNET) constraint on June 15 and an end-to-start dependency on another task can start on June 15 if its predecessor is completed by June 15 (or later if its predecessor ends after June 15), but it cannot be scheduled before June 15. This can e.g. For example, a suitable use of restrictions would be if you have planning permission that is only suitable for specific dates. In this case, the SNET or FNLT constraints can be used.

With the default finish-to-start task relationship and an ASAP constraint applied to these tasks, the successor task (the second) is scheduled to start as soon as the predecessor task (the first) is completed.

If the SNET restriction is applied, the successor task cannot begin before the restriction date, even if (as shown here) the predecessor task is completed before the restriction date.

The following table lists the limitations provided in Project.

Restriction type

Restriction name

description

Flexible

As late as possible (SSWM)

The task starts as late as possible, with the task ending before the end of the project and without delaying subsequent tasks. This is the default task constraint when the project is calculated from the project finish date. Do not enter a start or finish date for this restriction.

Flexible

As early as possible (SFWM)

The process starts as early as possible. This is the default task constraint when the project is calculated from the project start date. Do not enter a start or end date for this restriction.

Semi-flexible

Start not earlier than (ANFA)

The process begins on or after a specified date. With this restriction you ensure that a task does not start before a specified date.

Semi-flexible

End not earlier than (ENFA)

The process ends on or after a specified date. With this restriction you ensure that a task does not end before a specified date.

Semi-flexible

Start no later than (ANSA)

The process begins on or before a specified date. With this restriction you ensure that a task does not start after a specified date.

Semi-flexible

End no later than (ENSA)

The task ends on or before a specified date. With this restriction you ensure that a task does not end after a specified date.

Firmly

Must end on (MEA)

The process ends on a specified date. The date you entered is set for the earliest, planned and latest finish dates, and the task is anchored in the schedule.

Firmly

Must start on (MAA)

The process begins on a specified date. The date you entered is set for the earliest, planned and latest start dates, and the task is anchored in the schedule.

By default, all tasks in a project that are scheduled based on the start date are subject to the SFWM constraint. The "As late as possible" (SSWM) restriction is also applied to all activities in a project that are planned based on the finish date.

Inflexible constraints usually override all task dependencies and limit a task to a date of your choosing. For example, a task with a Must Start On (MSO) restriction on September 30th and an end-to-start dependency on another task is always scheduled on September 30th, regardless of whether the predecessor is early or late is completed. You can change this behavior. click You on file,click on options,click on Time schedule,and then select the Tasks will always check box their restriction dates considered.

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How do activity types affect the schedule?

Activity types refer only to automatically planned activities, and there are three variants: "Fixed units", "Fixed work" and "Fixed duration". Project considers the activity type to determine how duration, work, and units interact in scheduling.

Each type of transaction affects the scheduling if any of the three items are changed as follows.

Transaction type

When changing units

When changing the duration

When changing work

Fixed-unit operations

Duration is recalculated

The work is recalculated.

The duration is recalculated.

Fixed work operations

Duration is recalculated

Units are recalculated

Duration is recalculated

Fixed-duration tasks

Work is recalculated

The work is recalculated.

Units are recalculated

  • To change the task type, double-click the task name on the Gantt chart, then click the tab Extended.

Some examples

For example, suppose you have a fixed-unit task with a full-time resource unit available for 8 hours a day. You set up the process with a duration of 10 days and a total of 80 hours of work.

  • If you learn that there is another full-time supporting resource available for this task, Project will recalculate the task duration. The task is now assigned 2 units for a duration of 5 days with a total of 80 working hours.

  • If the task is to be completed in just 8 days instead of 10, Project recalculates the task work. The task now has a duration of 8 days with a total of 64 hours of work and one resource unit.

  • If the task requires 20 hours of additional work, Project recalculates the task duration. The task now has 100 hours of work with a duration of 12.5 days and one resource unit.

For example, suppose you make the same task a fixed work task. This means that the process can only take in the amount of work you have specified: no more, no less. In this example, the task has a full-time resource for 8 hours per day and a duration of 10 days with 80 hours of work.

  • When you learn that another full-time resource is available for this task, Project recalculates the task duration. The task is now assigned 2 units with a task duration of 5 days and a total of 80 working hours.

  • If you only have 8 days instead of 10 to complete the task, Project recalculates the resource units for the task. In order to carry out the process in 80 working hours over 8 days, 1.25 resource units must be assigned. The currently assigned resource unit is assigned 125%. Allocate another resource to account for the additional 25% allotment.

  • If the task requires 20 hours of additional work, Project recalculates the task duration. The task now has 100 hours of work with a duration of 12.5 days and one resource unit.

For example, suppose you make the same task a fixed duration task. This means that the process must be completed in the time you specified.In this example, too, the task has a full-time resource for 8 hours per day and a duration of 10 days with 80 working hours.

  • If you find that another resource can assist with the task, Project recalculates the work assigned to each resource. When only one resource was assigned to the task, that resource had 80 hours of work. If you assign a different resource to the task, each resource has 40 hours of work that must be completed over the same 10-day period for a total of 80 hours of work. By adding another resource unit, you also revise the allocation of both units to 50% each, which means that both are 50% available for work on other tasks.

  • If the task is to be completed in just 8 days instead of 10, Project recalculates the task work. The task now has a duration of 8 days with a total of 64 hours of work and one resource unit.

If the task requires 20 additional hours of work, Project recalculates the resource unit for the task so that the additional work can still be completed within the task's 10 day duration. The task now has 100 hours of work with a duration of 10 days and 1.25 resource units. The currently assigned resource unit is assigned 125%. Allocate another resource to account for the additional 25% allotment.

Note: Because cost resource assignments do not have values ​​for work or units, these values ​​are not recalculated if the start or finish date is changed. Data is also not recalculated for a cost resource assignment because the work or units cannot be changed.

The following table contains important points about transaction types that you should always keep in mind:

Tips and Tricks

Explanation

Pay attention to performance-driven operations

If you in the list Transaction type on Fixed work click, you can change the setting Performance-driven for the operation do not change. Fixed work tasks do not have flexible work values ​​and are therefore always performance-driven. For more information on performance-based operations, see later in this article.

Add a column to make it easier to change the transaction type

You can display and change the transaction type for each transaction directly in the current view by pressing the field Art insert. Click the column to the right of where you want to insert the new column, and then click the menu Insert on column. Click in the list Field name on Art.

Summary tasks are always tasks with a fixed duration.

Summary tasks are always tasks with a fixed duration, since the start and end dates of summary tasks are determined by the sub-tasks.

Do not use task types to break down tasks, but rather by indenting them.

If you want to change the hierarchical structure of a task or sub-task in the outline structure of a project, you must demote or promote the task instead of changing the task type or add a deadline.

Do not confuse activity restrictions such as SFWM with activity types

If you want to specify restrictions on the calculation of start and finish dates for tasks in Project, you must set a task restriction instead of the task type.

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How does performance-driven scheduling affect the schedule?

After a resource has been assigned, all tasks are scheduled according to the following formula (assuming the default task type "Fixed Units"):

Duration = work / units

For each task, you can choose which part of the formula Project will calculate by specifying the task type. When you assign or remove people from a task, Project extends or shortens the duration of the task based on the number of resources assigned to it, but Project doesn't change the overall work for the task. This is known as performance-driven scheduling. This setting is usually deactivated. To activate it, click on File,click on Options,click on Time schedule,and then select the New Issues check box are effort-controlled.

While performance-based scheduling works in most scenarios, you may want to change this to observe more closely how adding or removing resources affects an operation. You may want to increase the overall work as you add people to a particular task.

  1. Right-click a task, click Task information , and then click on the Advanced tab.

  2. Uncheck the box Performance-controlled.

Note: You cannot turn off performance-based planning for fixed work tasks. Fixed work tasks do not have flexible work values ​​and are therefore always performance-driven.

When using performance-based planning, note the following points:

Tips and Tricks

Explanation

"Performance-driven" does not refer to the first resource assigned

The performance-based calculations are only applied after the first resources have been allocated to the task. After the first resources are allocated, the work value no longer changes when resources are allocated or removed from the same task.

Watch out for fixed-unit operations

With the assigned transaction type Fixed units assigning additional resources will shorten the duration of the task.

Look for tasks with a fixed duration

With the assigned transaction type Fixed duration allocating additional resources reduces the individual unit values ​​for resources.

Pay attention to fixed labor operations

With the assigned transaction type Fixed work assigning additional resources will shorten the duration of the task.

Some operations can be manually set to "Performance-driven"

For summary tasks and inserted projects, the option Performance-controlled cannot be set.

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How does manual and automatic planning affect the schedule?

To understand how Project plans your project, it is important to understand the difference between Manually Scheduled Task and Automatically Scheduled Task.

In general, manually scheduled operations give you control over the schedule. If you add a task to your schedule, it will stay. However, this isn't always the best way to design a schedule, especially when projects get more complicated where you may want to use automatically scheduled tasks to take advantage of Project's powerful scheduling engine.

Take a look at the graphic below. It shows two different types of transactions, the first two of which were planned manually and the second two automatically.

Note that the duration of the manually scheduled tasks is both a text value and a number. Because duration can be a text value, Project did not automatically set a start date, and the task bar is only partially displayed to reflect the uncertainty of task planning at this point.

In the case of the automatically planned process, the duration is a numerical value, to which a time unit such as "12 hours" was assigned for a period of twelve hours. Duration, start and finish dates are evaluated by definition for automatically planned tasks and the task bars are therefore drawn automatically by Project.

Now things get a little tricky with the information you provide for manually scheduled operations. To draw the bars for a manually planned task, Project only needs three values: duration, start date, and finish date. If you include two of these values ​​in a manually scheduled task, Project will automatically calculate the third value and the task will still be considered manually scheduled. So watch out for this kind of "unusual" behavior from Project.

Note: Activities are scheduled manually by default. Project managers who are familiar with the automatic planning functionality from older versions of Project can turn off the manual planning functionality for specific tasks or for the entire project. Some projects, especially more complex ones, may require Project's powerful planning engine to oversee the planning for you. To schedule all tasks automatically, click at the bottom of the Project application window New tasks: schedule automatically.

Manually planned operations

You can place a manually planned activity anywhere in your schedule; Project then maintains this position. This new feature provides more flexibility and control over the planning and management of schedules.