Unlike a Milestone, you do not enter a completion date (Finish Date) when inserting a constraint, only the estimated task duration. Once the duration is entered, the Start and Finish Dates for the task are computed by SPS|PM. Since each Milestone has a defined completion date, the date calculation for a work stream starts with the Milestone and works backwards to the beginning of the work stream. Each constraint (task) in the work stream is assigned a Start Date and a Finish Date based on its duration and the Start Date of its successor. For the three possible methods for calculating the Forecast Dates for tasks in a workflow, see also: Continuous Workflow Calculation Method, Last Responsible Moment Workflow Method, and Setting or Changing Forecast Dates.
When entering durations for constraints, you can specify task durations in fractions of days in order to accurately plan several activities within a single day. This feature supports daily Production Planning and the 1-day Planning Horizon of most production teams. When assigning a task duration, keep in mind that for an 8-hour workday (determined by the default calendar, team / member calendar and task calendar), a task duration of 1.0 is equal to 8 hours of work, a duration of 0.5 is 4 hours of work, a duration of 0.1 is approximately one hour of work, etc. Work week is also configured by the default calendar, team / member calendar and task calendar). When calculating Start and Finish Dates, the system automatically takes into account the length of the work-week, and does not assign any Start or Finish dates to the weekend. If desired, however, the work-week length can be configured on a team-by-team basis through the Team Calendar functionality as described in Manage Team Calendar.