This article answers multiple questions related to task dates and durations.

Why can I not (directly) update (all) Task Date Fields?

Which task date fields are controlled by LYNX and which are controlled by me?

Scheduling Dates: Set or “owned” by LYNX / Indirectly Controlled by the User:

• Baseline Date Fields
• Scheduled (or expected) Date Fields
• Actual Start/Stop Date Fields

Directly Controlled by a user: Task Constrained Date Fields, like:

• Start-no-earlier-than (SNET)
• Finish-no-later-than (FNLT)

What impacts the dates when LYNX is scheduling the dates?

The dates set by the LYNX Scheduling Engine consider the following factors:

• The current Date
• Which Scheduling Engine which is activated 
• The Scheduling Direction of Critical Chain and/or Feeding Chains:
  
  • ASAP (Forward)
  • ALAP (Backward)
• Scheduling Optimization for determining the earlies/fastest completion date

The dates "indirectly" controlled by the user are impacted by the setting of the Project Start and/or Project End dates and the selection of the scheduling direction.

Explanation: The scheduling direction can be set for each project in the project properties. Under the scheduling tab, you can  (as long as the project status is "Not Started") choose the schedule engine to schedule tasks "as soon as possible" for the ASAP (Forward) direction, and "just in time" for  the ALAP (Backward) direction. 

This is different from the CCPM scheduling, in which you can also choose the feeding chains to be scheduled "as soon as possible" or "Just in Time" separately from the scheduling direction. This setting you can change when the project status is not started but also when started.

Using "Just in time" is considered the best practice based on the Theory of Constraints methodology.

 

What are some guidelines for task constraints?

• Start-no-earlier Constraints work well when scheduling direction for a “chain” is ASAP (Forward)
• Finish-no-later-than Constraints work well when scheduling direction is ALAP (Backward)
• Less Constraints would be needed if any task has a predecessor and successor

See question above "What impacts the dates when LYNX is scheduling the dates?" for explanation of the scheduling directions.

 

Can you give an example?

We will discuss the following scenarios in the example:

• When the project status is "Not Started"
• When the project status is "Released"
• When the date has progress with + 6 days, and Task 2 is started

Let's consider a project which has 2 tasks; Task 1 and Task 2. Task 1 has a duration of 10 days and a constraint "Start no earlier than" (a date controlled by the user). Task 2 has a duration of 5 days and no constraints.

When the project status is "Not Started":

Explanation: The constraint dates are set by the user, so is the task duration. From this, The LYNX Scheduler will set the Baseline Start and End date using the current date for the Baseline, and the end date as the current date + 10 days (the task duration). The Scheduled date is also controlled by the LYNX Scheduler, but since the project is not released yet, the fields are empty.

When the project status is "Released":

Explanation: The Baseline dates are saved upon the release date of the project, so the current date. However, now that the project is released, the scheduled dates are also set by LYNX. 

When the date has progress with + 6 days, and Task 2 is started: 

Explanation: The current date is now 6 days from when the project was released. The scheduled dates get automatically updated as the time progresses. When Task 2's status is set to "Started", the actual start date is saved as the date of when the task was started. This date can be updated by the users.

 

Other FAQ:

What is the difference between baseline date, expected date, and actual date?

• Baseline start and end dates are the current date and time. This is saved once the project is released.
• Expected dates are automatically set by LYNX once the project is released and they are dynamically updated based on time progression and the progress of the project.
• Actual dates are when the task was set to started/completed. This is the actual dates the tasks were started and finished set by the user.

 

How do I change the date format for the start and end dates in the Gantt chart view? I would like to eliminate the hours and use a numerical date.

You can change this in the Space Properties via the Turn Features On/Off tab. The steps are:

1. Go to configuration via the top right or in the menu.
2. Go to Space properties.
3. Choose the Turn Features On/Off tab.
4. Under support hours, uncheck "Shows the hour on datetime values"

This will remove the hours in the task list and in the task properties timestamps, but not in the task list columns in the project. It is not recommended to change dates in the columns, but rather in their specific tabs, for example via the constraint tab of the task properties.

Note: This is a global setting on the space, so it will affect all projects in the space.

Note: This setting means you cannot see the hours in the dates tab in the task details or in the task lists anymore, however, you can still see them in the date columns.

 

What does it mean for the task duration being in square brackets?

As long as no skill or resources are assigned, you can update the Prj Duration directly in the column or in the task properties. Once a skill or resource is assigned to a task, the duration is controlled by the Estimated Time of the “Resource Requirement(s)” or ETTC of the “Resource Requirement”. You can see this in the task properties, under the resource requirement tab.

You can no longer edit the duration of a task via the duration field, but in the resource requirements.

The background of this flow is make the process as efficient as possible: when a task is created it typically gets a first estimate (let’s say 10 days). The next step is to assign resource/skills. And just by drag and drop of one or multiple resource requirements (skill/resources) each of them inherits the same estimated duration (10 days).
So as a user, you don’t have to add estimates again and again for each and every resource requirement.

 

Can I enter the estimated completion date (enter a date and not a duration) when in the Gantt view?

You cannot enter the estimated completion date for a task in the Gantt view. However, in the “Active Tasks” tab, under the task details, you can enter the estimated completion date.

 

Why does ETTC of a task show [Tomorrow] in front of the days/hours?

This is seen after editing a task's "Expected completion" or "ETTC" in the task details in "My activities", in "Active Tasks", or changing the expected time to complete of a resource/skill in the resource requirements of a task in the project view. Tomorrow means that if you enter today an ETTC value of 5 days, it is interpreted as 5 working days from tomorrow. This means the ETTC value you enter should exclude today.

 

Is the ETTC calculated in calendar days?

The ETTC calculates working days as a duration. It is possible to tune the expected amount of work (hours) by changing the "unit" percentage of the resource/skill assigned to a task.

The working day can be edited in the "Calendar" in configuration. This is set space wise, but you can can create multiple calendars and pick a specific calendar for each project. In the calendar, you can edit the working hours and add rules, for example, Resources do not work on 25 and 26 December.

 

Explanation: From Configure > Calendar, you can create new calendars, add edit and delete rules, and add working hours. 

Explanation: When creating a project, or in the properties of a "Not Started" project, you can select which calendar to apply to the project.

 

Explanation: In the project view, in the task details under the "Resource requirements" tab, you can add resources and skills. You can double click and change the "Units" percentage assigned to the resource. You can also change the units in the task details in "My Activities" and "Active tasks".

See article: Calendar, Time and Durations – Support Center for more details.

 

With the ETTC or Estimated Completion date for a task, will that date automatically change as time passes? Or do I need to manually change it?

The default process of updating tasks is via the “Finish by” dialogue, in which you can enter either the expected completion date or the remaining duration of a task, see description below:

In this dialog the ETTC value and Expected Completion value are connected and synchronized automatically:

• If a date is entered of + 5 days (1 week) from now, the ETTC is automatically set at 5 duration days.
• Or, if an ETTC is entered of 5 duration days, the Expected Completion date is set at + 5 days.

As a consequence, if you do not update the remaining duration of a started task (or Finished by date), the expected finish date of a task will move every day with + 1 day, and the complete critical chain will move with + 1 day (assuming the task is a critical task), also resulting in more buffer consumption.

As an organization, you can choose a frequency for updating tasks: some customers do it every day and others do once a week for example. There are pro’s and con’s for the frequencies, but a higher frequency is recommended.

Note: if you set a task to autocomplete, LYNX will count down the tasks automatically once started. But typically autocomplete is set for long duration tasks.

 

Can I see the project in the past?

There are two ways to see the project in the past; tags and selecting "current" date and time. For tags, you need to enable the auto-scheduler (Configure > Space properties > General > Enable auto scheduler). This lets LYNX to create a "snapshot" (tag) of the released projects at the specified time every day. It is recommended to set the time to 4 am, then you will be 100% sure there are no more updates or changes done to the project. Once this is set up, you can open the project, select the tag from the dropdown, and you will see the "snapshot" of the project in the past.

 

To enable auto scheduler: 

Example of a project with a tag selected:

 

The other way to see the project in the past (or future) is to change the "current" date and time LYNX scheduler sees. At the bottom of the LYNX window, you see the current date and time. Clicking that will open a window which lets you select another date and time. You can select a past date or a future date to see what the project looked/will look like and what the projects statistics were/will be. To reset this date, you can open the window again, and select current date + time.

 

What happens when I enter zero duration for a task, why will LYNX not accept the change?

Entering "0" duration for a task will change it to a milestone. If the change of duration is not accepted, it could be that the task has resource requirements (skills or resources) added to it. In that case, you can only control the duration via the "Resource Requirements" tab in the task details. If you set the estimate time for the assigned skills/resources, then the task will appear as a milestone.

 

Related articles:

• Calendar, Time and Durations
• Workpackage duration calculated from Expected Completion Date cards
• Understanding task timestamps (dates)