Are you aware that the majority of projects develop a schedule but actually don’t have a plan?
Often projects produce a version of a project plan which covers both planning and scheduling. They are not able to differentiate one from another when required.
How is project planning different from scheduling? What are the best practices in project planning today?
The difference between planning and scheduling is that planning addresses what will be done and how it will happen, while scheduling addresses who will do it and when.
How to apply this in practice? How could we develop a project plan without start and end dates?
The best practice is to develop a project plan as a DYNAMIC PROJECT DELIVERY MODEL (DPDM) and then to apply different techniques to schedule activities.
Project Delivery Plan
A planner builds a project delivery plan as a dynamic project delivery model (DPDM).
The model defines:
- Project scope breaking into manageable pieces (tasks, activities, deliverables, user stories, etc.). Let’s call them ‘activities’ in this post
- Characteristic for each piece (skills, volume, limits, materials, etc.)
- Project constraints (logic, committed dates, resource, material and financial limits)
- Project Risks & Opportunities
The model doesn’t define:
- Assigned resources
- A target sequence of work
- Target start and end dates of activities
A scheduler assigns resources (based on supply, demand and priorities), adds actuals, and calculates the start and finish dates for outstanding activities.
Schedulers use different techniques to find out the best combination of resource assignments.
Schedulers are often limited by a scheduling tool they have to use. This tool often determines a possible level of schedule optimisation. Advanced scheduling tools are able to calculate Resource Critical Path and identify the earliest delivery options.
The project delivery model defines the type of required skills but doesn’t have any specific resources assigned yet. Available resources are usually grouped by their skills and listed in resource pools.
Activities in a DPDM model don’t have target durations, except when this is required by a technology process. Duration of activities is only calculated when a resource(s) assigned!!!
Start and Finish dates
Planning defines technological constraints:
- Logic between activities: you must be pregnant before giving a birth
- Skills: you need to be a woman to be able to deliver a baby
- Technological limits: 2 women can’t deliver a baby in 4.5 months
Scheduling defines current limits & priorities:
- Resource & material limits: SMEs are limited, etc
- Financial limits: allocated budget, executive contingency, etc
- Priorities: values
A sequence of activities depends on:
- Technological constraint
- Current limits
- Duration of activities
The start and finish dates of each activity depend on the sequence and durations of activities.
Also, there are some other items to consider while planning & scheduling:
- A resource may have different skills and to be assigned to different resource pools. Also, a resource may have a different productivity rates in different skills:
Resource Alex has skill “X” with productivity 100% and skill “Y” with productivity 50%
Resource Julia has Skill “X” with productivity 50% and skill “Y” with productivity 100%
Resources Alex and Julia assigned to Resource Pool “X” and Pool “Y”
- Some activities could be completed more than one way or with a different type of resources:
We could dig a trench with a bulldozer or a spade.
- Type of resource may have different productivity rate:
Bulldozer – 1 km/h, spade – 0.1km/h
- Some activities could be performed as a team only:
Car and driver
- Resource assignments, a sequence of work, start and end dates of activities are dynamic characteristic of the project plan. However, sometimes it is useful to fix assignments and dates, even though the better option is available.
- It is useful to store resource characteristics (cost, skills, productivity) in corporate reference books and reuse them for different projects. Project actuals could be used to review and adjust the corporate norms.
- Fragments of DPDM could be reusable for different projects and significantly speed up a project development process.
- DPDM could be developed as a single version or may include more than one scenario (sequence of work).
- An ideal scenario is based on unlimited resources, realised opportunities and mitigated risks and defines the earliest delivery dates. The probability that the project will be completed as per the best scenario is close to zero but it is useful to understand theoretical limits. Better results could be achieved only with a change of scope.
- The quality of DPDM depends on methods to collect and maintain project data, features in a planning tool and the skills of a planner to develop the plan.
A low maturity schedule could be developed without planning and used for tracking project activities.
However, if a project needs to have a high maturity schedule, that can be used for analysis and decision making, then the Dynamic project delivery model is the best approach. It allows performing “what-if” analysis very quickly without a need to rebuild a schedule every time when changes required.