The most common scheduling approach starts at the beginning and calculates forward. Users enter a key date, link the tasks, and then adjust durations to determine future effort and timing.
Conceptualizing and executing a linear schedule is the simplest solution because the starting key date is within reach. But there are drawbacks. A linear schedule may create pre-key blackouts and can require continual adjustment of the projected durations as the fog of the project clears and more unknowns become known. For example, trying to open X number of stores in the third quarter would require some black magic to produce schedules that calculate from the start to end up in that timeframe.
Here are three ways to confront this issue:
- Set a baseline independent of any projections.
- Make durations easy to understand and update.
- Allow manual override of any projected date.
Setting a baseline (I like to call this an independent calculated stream based on the key date) independent of the projected schedule allows project managers to compare any future adjustments made to durations in the projected calculated stream. It’s a great way to see what was expected and what actually occurred. Future project schedules can leverage the difference between your baselines and actual to make your projections even more accurate in the future.
Design the calculations between the milestones to be easy to understand and update. Sometimes companies can get a bit carried away and over-design the number of independent conditions that each date reviews before selecting a date. It does make the schedule more accurate, but it also increases the workload of your staff in keeping your projections accurate. In these cases it’s not as simple as updating a single duration. You would need to update the duration for each valid independent condition. Keeping it simple makes this issue less of a concern.
If the user doesn’t care about the duration, but simply knows the date they will have the permit in hand, allowing the user to simply override a calculated date by manually entering the projected date (not adjusting the duration) is pretty straightforward. This allows the rest of the schedule to pick up and calculate the impact that date has on the projection.
From my experience to date, I have seen this method work best on larger projects with longer construction cycles or projects where the key date is a bit later in the real estate process – not right at the start.
Correctly modeling your projected schedules is critical. Having a flexible tool that can handle your requirements will centralize your efforts and save your team countless hours.
