One thing you may note as part of your upgrade process from 2007 to 2010 is that there are a number of custom fields that have been added to the Microsoft Project desktop client.  Why is that, you ask?  Well, it just happens that as part of the retooling to support the Manual Task Mode, a number of new fields were added.  Unfortunately or not, some of these fields took over the names of existing fields.  For a quick overview of some of the new fields, check out Jack Dahlgren’s post from last February.

This post is intended to give a quick overview of some of the field changes in 2010, specifically with regard to the date fields such as Start and Finish.  Note that there are conflicting sets of documentation in circulation, which will probably serve to confuse end users.  That will be addressed later in this posting.

So, where before we had the Baseline Start and the Start fields, we now have four fields:

  1. Start
  2. Scheduled Start
  3. Baseline Start
  4. Baseline Estimated Start

…with, of course, the same principle applying to the Finish and Duration fields as well.  These fields were all added to support the new Manual scheduling mode available in Project 2010.

What do they all mean?

Well, let’s take the easy ones first:

The Scheduled Start field is what we all knew in the old days as the Start field.  The Scheduled Start field displays the date on which the task would start if it observed links, constraints, and network logic, i.e. the Schedule Start field is the Automatically Scheduled Start field.  Even when the task is set to Manually Scheduled, the Scheduled Start field is still calculated.  When the task is set to Automatic, the Start field equals the Scheduled Start field.

The Start field, on the other hand, despite having a familiar name, is actually a new field.  That is the date upon which the task is set to start as per the Manual settings.  One could, I suppose, calculate the difference between the Start and Scheduled Start to assess how optimistic (aggressive, self-deceiving, etc.) an organization really is.  Again, for Automatic tasks, Start equals Scheduled Start.  For Manual tasks, Start actually equals whatever you feel like entering, up to and including text such as “Need to ask Bob for revised estimates.”

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I can even enter text in the Start and Finish fields now:

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(Haikus posted by Rick Brenner at his site:  http://www.chacocanyon.com/essays/tenprojecthaiku.shtml)

Baseline Start

Simple right?  So how do the Baseline Estimated Start and the Baseline Start fields work for Manual tasks?

The Baseline Start field is a copy of whatever was in the Start field when you saved the baseline.  If you have text data, then Baseline Start contains text data.  If you have a date, then Baseline Start contains date data.  And if the Start field is blank, then Baseline Start will assume the last date entered in the Start field.  If no date has ever been entered in the Start field, the Baseline Start will take the Project Start date or the Summary Task Start date.

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….which is perhaps a bit confusing.  Here’s a handy decoder table:

IF Start=… …THEN Baseline Start =…
Text Start
Date Start
Blank (No Data Ever Entered) Start (i.e. blank)
Blank (Data Entered, but Cleared) Start (i.e. blank)

Relatively straightforward enough, I suppose.

Baseline Estimated Start

The trickier question is understanding what goes into the Baseline Estimated Start field.  There are a couple of theories floating around as to what gets populated in that field.  I’ve seen a couple of these theories documented in print and online:

Theory #1: The Baseline Estimated Start field gets populated with the Scheduled Start field.

Theory #2: The Start field gets populated to the Baseline Estimated Start field if the Start field is populated with a date.  If the Start field is not populated with a date (i.e. text has been entered), then the Baseline Estimated Start field will be populated with the data in the Scheduled Start field.

As far as I can tell from my testing, both of these theories are false as the product currently is designed.  In some specific circumstances, I can make the data look like either of these theories have been applied, but in actuality, here’s the observable, testable rule for how the Baseline Estimated Start field works:

The Baseline Estimated Start field is populated by the last date entered in the Start field.  This means that even if the Start date is blank, there’s a phantom entry somewhere in the system that records the task was originally scheduled for the Project Start date.  As a result, when I baseline a project, the last date entered in the Start field is copied to the Baseline Estimated Start field.

In the following example, I have text entered in the Start field.  As a result, the Baseline Estimated Start defaults to the last date data stored in the Start field, which would have been the Project Start date.

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….which is actually less confusing than the Baseline Start.  Here’s another handy decoder table:

IF Start=… …THEN Baseline Estimated Start =…
Text (No Date Ever Entered) Project Start (or Summary Task Start)
Text (Date Entered Previously) Last Date Entered
Date Start
Blank (No Data Ever Entered) Project Start (or Summary Task Start)
Blank (Date Entered, but Cleared) Last Date Entered

You will note that the act of clicking on Respect Task Links will overwrite text in the Start field and insert date data.  When the Start field is overwritten by text, the date data still gets transferred over to the Baseline Estimated Start field.