The Challenge of Constraint
Two weeks ago I had a call with one of our prospects where he discussed the challenge he faces when scheduling his project plan according to the tight availability of his resources. I took the opportunity to demonstrate the way work planning work policy can be approached and how it can be done in Clarizen.
I’ve noticed that you can generally articulate most real life scenarios using the same 3 line triangle diagram. Work Management is no different - although what we look at does change. For R&D, the 3 metrics are Time, Resources and Scope. If you change any 2 of the metrics, the third has to change accordingly.
When managing projects we see the project’s triple constraints of Time, Resources and Budget:
For example, a project that has to be handed off at a certain date (e.g.: convention date, customer commitment, etc) is typically date driven and might even be planned from the delivery date backwards, while another project plan that is dependent upon its resources may be driven by the resource’s availability.
Clarizen allows you to choose your planning approach as the primary working policy and you can then define, on a case per case basis, a secondary constraint and then calculate your project plan accordingly. It’s like using the equationDuration x Resource = Work.Check out Hal Macomber’s Blog post on Understanding Project Constraints:
Clarizen lets you define your organization’s default work policy but also allows you the flexibility to override it at the project level and even at the individual work item level. This gives you the maximum flexibility to adapt your plan to its appropriate approach according to its phases and milestones.
The 3 working policies your project plan can follow are:
- Driven by resource’s defined availability – In this scenario a resource’s availability (in % - AKA: unit) is static and the planned invested work and duration are calculated accordingly (having each of them being the potential secondary constraint). For example: Joe can work only 60% of his time on ‘Feasibility Analysis’ task and the task has to be finished within 5 working days to meet a certain deadline. Joe’s effort level will then be dictated by the two static elements. In this case the: work = Duration x Unit(Joe) , assuming Joe works 8 hours a day, then his work load would be 24 hours = 5 days x 8 hours* 60%. Since the duration is the constant we call it a “Fixed Unit”. A unit is defined as the level-of-effort that is needed to complete a task. It is represented as a percentage of full effort.
- Driven by work content and effort – In this scenario the level of effort required to execute this task is static, letting the planned dates (duration) and resource’s load be calculated accordingly (having each of them being the potential secondary constraint). For example: Executing a “Customer Training” task should take 20 hours of work, as it was committed to the customer with a committed scope and budget related to it. The resource’s defined availability will determine the length of this training task. Suppose Joe will conduct this training and he will spend 100% of his time on this task and he works 5 hours a day, that would mean the duration of this training will be 4 working days = 20/(100% x 5 h). Since the work is the constant here, we call it “Fixed Work”.
- Driven by dates – In this scenario a task has to take place during a specific time frame making the duration the static variable and letting the work and resource’s load be calculated accordingly (having each of them being the potential secondary constraint). For example: an ‘RFP Answer Letter’ task within a quotation milestone must be finished within a certain number of work days. The resource’s defined availability will determine the work investment for this task or vice versa – the work required to execute this task will determine the resource’s load on the task (Aren’t we always overworked when working on a customer’s RFPJ?!). Since the duration is the constant here, we call it a “Fixed Duration”. Check Elizabeth Herrin’s Expert advice on fixed date projects.
In Clarizen you can have two types of tasks: those that you have a set start date and those that have a set end date. You might have a start date when you’re planning ahead from a given date until whenever the project ends, and you might have an end date when you’re planning towards a given date. For example: you would use a set end date when you have an event that you have to be ready for and you need to decide when you need to start the project in order to be on time. The two alternatives for planning are called As Soon As Possible (ASAP) for projects with a set start or As Late As Possible (ALAP) for projects with a set end date.
In Clarizen’s next release V4.8 coming out soon, we have added personal calendars that will allow you to define the availability on the organization, group, personal and project level. This function will give you the ability to incorporate different staffing work restrictions as well as public and personal vacations into your work plan, ensuring it is up to date, reliable and reflects reality.

