Questions you can answer by modelling resources

Modelling resources enables you to make trade-off decisions, such as weighing up the pros and cons of assigning more resources to a task and the impact this could have on costs and project finish dates. Modelling resources can help you answer questions like the following.

How long will it take to complete a task?

I have four painters available to work on a task that would take one painter fifty hours to complete. How long will the task take to be completed?

  1. Create a task 50h long and assign the Painters permanent resource to it.
  2. Using the Modelling tab of the Permanent Allocation Properties dialog, configure the allocation as follows:
    • Modelling type: Effort on Allocation.
    • Calculated Parameter: Duration.
    • Balancing Parameter: Effort.
    • Allocation: 4.

Asta Powerproject calculates that with four painters allocated to the task, it will take 12h 30min to be completed. Note that if the number of available painters changes subsequently and you edit the allocation, Asta Powerproject recalculates the duration of the task automatically.

How much longer will it take to complete a task if I have fewer resources available?

I currently have eight electricians assigned to a task, but I have since found out that only five will be available. How much longer will the task take to be completed?

  1. Create a task and assign the Electricians permanent resource to it.
  2. Using the Modelling tab of the Permanent Allocation Properties dialog, configure the allocation as follows:
    • Modelling type: Effort on Allocation.
    • Calculated Parameter: Effort.
    • Balancing Parameter: Allocation.
    • Allocation: 8.
  3. Change the duration of the task by dragging it in the bar chart until the allocation falls to 5 or below.

How many resources do I have to assign to a task for it to be completed on time?

Example 1: with a single resource assigned

A task has the following attributes:

  • Task: Formwork; duration: 37.5 hours.
  • Formwork: 300 square metres; output per carpenter: 2.5 square metres per hour.

How do I find out how many resources I need to complete the task?

In this example, as you only have a single resource assigned to the task you set the amount of work that is required on the task itself and calculate the allocation using the Work From Task modelling method:

  1. Set up a work unit within Library Explorer called Square Metres.
  2. Set up a permanent resource in Library Explorer called Carpenters.
  3. Create a task with a duration of 37.5 hours. Using the 'Effort & Modelling' section of the Task tab of the Bar and Task Properties dialog, set the Task work to 300 and the Work unit to Square Metres to show the amount of work that needs to be done on this task.
  4. Assign the Carpenters permanent resource to the task. Using the Modelling tab of the Permanent Allocation Properties dialog, configure the allocation as follows:
    • Modelling type: Work From Task.
    • Calculated Parameter: Allocation.
    • Work unit: Square Metres.
    • Rate type: Units per time unit.
    • Work rate: 2.5 Square Metres per hour.

The allocation is updated to show the number of carpenters that you need to assign to the task: 3.2.

Example 2: with two resources assigned

A task has the following attributes:

  • Task: Formwork & Reinforcement; duration: 37.5 hours.
  • Formwork: 300 square metres; output per carpenter: 2.5 square metres per hour.
  • Reinforcement: 0.4 tonnes; output per steel fixer: 0.045 tonnes per hour.

How do I find out how many resources I need to complete the task?

In this example, as you have two different resources assigned to the task you cannot set the amount of work that is required on the task itself, as each resource has to do a different amount of work. In this case you must set the amount of work that is required for each individual allocation and calculate the allocation using the Work on Allocation modelling method:

  1. Set up two work units within Library Explorer called Square Metres and Tonnes.
  2. Set up a permanent resource in Library Explorer called Carpenters. Using the Assignment tab of the Permanent Resource Properties dialog, configure the resource as follows:
    • Modelling type: Work on Allocation.
    • Calculated Parameter: Allocation.
    • Work unit: Square Metres.
    • Rate type: Units per time unit.
    • Work rate: 2.5 Square Metres per hour.
  3. Set up a permanent resource in Library Explorer called Steel Fixers. Using the Assignment tab of the Permanent Resource Properties dialog, configure the resource as follows:
    • Modelling type: Work on Allocation.
    • Calculated Parameter: Allocation.
    • Work unit: Tonnes.
    • Rate type: Units per time unit.
    • Work rate: 0.045 Tonnes per hour.
  4. Create a task with a duration of 37.5 hours and assign the Carpenters and Steel Fixers permanent resources to it.
  5. Right-click the Carpenters allocation to display the Permanent Allocation Properties dialog. On the Modelling tab, set the Work to 300 Square Metres. The allocation is updated to show the number of carpenters that you need to assign to the task: 3.2.
  6. Right-click the Steel Fixers allocation to display the Permanent Allocation Properties dialog. On the Modelling tab, set the Work to 0.4 Tonnes. The allocation is updated to 0.2, indicating that the Steel Fixer must spend a fifth of his time on the task for it to be completed.

How can I calculate the rate at which a resource will have to work?

I know how many carpenters I have available to work on a 37.5 hour long task and I know the amount of work that needs to be done. At what rate will the carpenters have to work in order to complete the task?

  1. Set up a work unit within Library Explorer called Square Metres.
  2. Set up a permanent resource in Library Explorer called Carpenters.
  3. Using the Assignment tab of the Permanent Resource Properties dialog, configure the resource as follows:
    • Modelling type: Work On Allocation.
    • Calculated Parameter: Work Rate.
    • Work unit: Square Metres.
    • Rate type: Units per time unit.
    • Allocation: 2.
  4. Create a task with a duration of 37.5 hours and assign the Carpenters resource to it.
  5. Using the Modelling tab of the Permanent Allocation Properties dialog, set the Work to 30 Square Metres.

The work rate is updated to show that two carpenters working on the 30 square metre task will have to work at a rate of 0.40 square metres per hour. If you increased the allocation, the work rate will be reduced accordingly.

How can I calculate the amount of work that is required to complete a task?

I know how the number of resources I have available, their work rate, and the duration of a task. How much work will the resources be able to carry out in the time available?

  1. Set up a work unit within Library Explorer called Square Metres.
  2. Set up a permanent resource in Library Explorer called Carpenters.
  3. Using the Assignment tab of the Permanent Resource Properties dialog, configure the resource as follows:
    • Modelling type: Work On Allocation.
    • Calculated Parameter: Work.
    • Work unit: Square Metres.
    • Rate type: Units per time unit.
    • Work rate: 2.5 Square Metres per hour.
    • Allocation: 1.
  4. Create a task with a duration of 37.5 hours and assign the Carpenters resource to it.
  5. View the Modelling tab of the Permanent Allocation Properties dialog, and note that the Work has been calculated automatically.

Note that the amount of work has been calculated automatically. If you increased the allocation, the amount of work would be increased accordingly.

How many lorries do I need to deliver the materials required for a task?

I know that a task requires 103m3 of concrete and that each concrete mixer lorry has a capacity of 8m3. How many lorries do I need to deliver the concrete?

  1. Create a 'Pour Concrete' task. Using the 'Effort & Modelling' section of the Task tab of the Bar and Task Properties dialog, set the Task work to 103, the Work unit to m3 and the Task work material to Concrete to show the amount of work that needs to be done on this task .
  2. Set up a consumable resource in Library Explorer called 'Concrete Mixer Lorry'.
  3. Using the Assignment tab of the Consumable Resource Properties dialog, configure the resource as follows:
    • Modelling type: Quantity From Task.
    • Task conversion factor: 8.00; Divide and Round.
  4. Assign the Concrete Mixer Lorry resource to the Pour Concrete task.
  5. View the Modelling tab of the Consumable Allocation Properties dialog. The Quantity field shows that 13 lorries are required to deliver the concrete required for the task.