Why so many poor schedules?
Schedule logic is not the issue, what makes our schedule models so poor is how we deal with resources. Without resources nothing is done. Schedules that do not take into account all resource constraints are incomplete and most probably wrong.
We favor simplicity over substance and give the project manager very poor schedules he must manually adjust as soon as he realized the plan is no good.
1. The project manager understands the difference between effort and quantity and the need for partial workloads. He will not plan the impossible while most software will allow the impossible under partial workloads.
2. No project manager is to delay an activity because his model delayed the start of the activity when out of 10 resources only 8 are available and it is feasible to work at a reduced pace with 8. He knows he will finish the activity earlier the sooner it starts.
3. EVM jargon is not used at the jobsite. Site people and project managers manage the schedule using a common language; productivity and volume of work is spoken every day. Schedules that hide what are the planned production rates are difficult to manage.
4. A project manager knows that if resources are consumed but not replenished the activities are delayed until more become available. He knows the difference between renewable and consumable resources. He understands people are not consumed by the activities but used temporarily to be released as soon as the activity no longer uses them; he knows these are renewable resources. He knows consumable resources are not automatically replenished as renewable resources do, he realizes the schedule must consider their availability at all times if to be feasible.
5. A project manager knows that without funds the project is stopped.
6. A construction project manager knows he shall not move out elevated slab forms from a building before the last pour have been placed and cured. He might not know that the scheduling jargon for such resources is spatial resources but he knows how to deal with it.
If the scheduler do not know the difference between effort and quantity, do not understand the need for partial workloads, do not realize the need for variable resource quantity and workloads for efficient scheduling, do not realize the existence of consumable resources, do not realize the need to have financial resources in place and what spatial resources are the chances he will deliver a poor schedule are high.
Unless the scheduler makes sure all resource constraints are adequately handled the project manager will have no other option than to improvise on the field.
For a more detailed presentation of these concepts and how already commercially available software can efficiently deal with all (and more) please refer to the following link:
https://www.slideshare.net/davilara11/enhanced-resource-planning [1]
Thank you for your attention.
Rafael Davila