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Planned Start Date Field? RRS feed

  • Question

  • Mark here from Perth, Doing some work for Trevor Rabey at PPP
    I just want clear definitions on the difference between the following four fields:

    Early Start
    Early Finish
    Planned Start
    Actual Start

    The more information on each the better,
    please help, Rod Gill, should be in your NZ time zone right about now!

    Regards

    Wednesday, February 6, 2013 12:33 AM

Answers

  • Mark, to expand a little on Michael's (accurate) answer:

    Early start is the start date for a task calculated from the Early finish date of its predecessor (assuming a Finish to Start dependency). If there's more than one predecessor, the Early start would be the later date calculated this way.
    Tasks A and B are each simple FS predecessors to Task C. A: Early Finish = 5 Feb; B: Early Finish = 7 Feb; C: Early Start = 7 Feb (or 8 Feb if B's early finish is at end of day).
    If there are date constraints on a task, this will confuse the simple task dependency calculation.
    For a task with scheduling constraint "As Soon As Possible" the Start date shown in the Gantt Chart Entry table will be the same as the Early Start date.

    Early Finish date is calculated from the Early Start date for a task with the addition of the task Duration. It is the earliest the task can finish, given the early start date. There are things that could upset this simple picture - a split task, for instance, does not include the size of the split in the duration but it does affect the early finish date.
    The task Finish date will normally be the same as the Early Finish date

    Planned Start is the term often used for the Start date - the one shown in the Gantt chart entry table and used for the default Gantt chart bar.

    Actual Start is the date that is reported for when the task actually starts. When you enter an actual start date, or set the % complete to other than 0 (not recommended practice) or an assignment for that task first has actual work reported against a particular day.
    The Start date will always be the same as the Actual Start date if there is one.

    You may want to read up on Critical Path calculation. The Early Start and Early Finish dates are calculated as part of the forward pass. Once the earliest project end date (the latest Early Finish date of ny task in the project), that is used as the beginning of the backward pass in which the Latest Finish and Latest Start dates are calculated.

    Wednesday, February 6, 2013 3:28 PM

All replies

  • Early Start  - start date if all predecessors finish on time
    Early Finish - finish date if all predecessors finish on time
    Planned Start  - start date bases on plan if using asap (as soon as possible)
    Actual Start- when task actual started

    Michael Wharton, MVP, MBA, PMP, MCT, MCTS, MCSD, MCSE+I, MCDBA
    Website http://www.WhartonComputer.com
    Blog http://MyProjectExpert.com contains my field notes and SQL queries

    Wednesday, February 6, 2013 1:18 AM
    Moderator
  • Mark, to expand a little on Michael's (accurate) answer:

    Early start is the start date for a task calculated from the Early finish date of its predecessor (assuming a Finish to Start dependency). If there's more than one predecessor, the Early start would be the later date calculated this way.
    Tasks A and B are each simple FS predecessors to Task C. A: Early Finish = 5 Feb; B: Early Finish = 7 Feb; C: Early Start = 7 Feb (or 8 Feb if B's early finish is at end of day).
    If there are date constraints on a task, this will confuse the simple task dependency calculation.
    For a task with scheduling constraint "As Soon As Possible" the Start date shown in the Gantt Chart Entry table will be the same as the Early Start date.

    Early Finish date is calculated from the Early Start date for a task with the addition of the task Duration. It is the earliest the task can finish, given the early start date. There are things that could upset this simple picture - a split task, for instance, does not include the size of the split in the duration but it does affect the early finish date.
    The task Finish date will normally be the same as the Early Finish date

    Planned Start is the term often used for the Start date - the one shown in the Gantt chart entry table and used for the default Gantt chart bar.

    Actual Start is the date that is reported for when the task actually starts. When you enter an actual start date, or set the % complete to other than 0 (not recommended practice) or an assignment for that task first has actual work reported against a particular day.
    The Start date will always be the same as the Actual Start date if there is one.

    You may want to read up on Critical Path calculation. The Early Start and Early Finish dates are calculated as part of the forward pass. Once the earliest project end date (the latest Early Finish date of ny task in the project), that is used as the beginning of the backward pass in which the Latest Finish and Latest Start dates are calculated.

    Wednesday, February 6, 2013 3:28 PM
  • One more point to note.

    Once you start recording progress in a project schedule the "Start" date reflects the "Actual Start Date" for tasks that are either complete or are in progress.

    For Tasks where there has been no progress the "Start" date is the currently scheduled or planned start date which may differ from the "Baseline Start Date" which should reflect what the "Planned Start Date" was prior to the project actually starting. The Actual Start date for such tasks will display as N/A.

    Hope that is clear - reading it back it sort of makes sense.

    In essence a project plan initially reflects what you would like to see happen, once a project is in progress it reflects what has happened and what is planned to happen and on completion it should be a record of what happened.

    Ideally you compare actual progress against the Baseline throughout the project lifecycle to exhibit control and on completion compare actuals against the baseline to identify variances, ideally knowing what caused the variances so that you can learn from the experience.

    If we do not learn from history we are condemned to repeat it - Georges Santayana


    Dominic Moss MAPM, MCTS, MCITP, MCT
    Wellingtone PM News
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    Wednesday, February 6, 2013 7:57 PM
  • There you go Mark. A demonstration of effective delegation for you. Good job team, great answers! ;-)

    Rod Gill

    The one and only Project VBA Book

    Rod Gill Project Management

    Thursday, February 7, 2013 4:03 AM
    Moderator