Assigning process time along with resource rate and cost
In order to help you capture the length of time of business processes, processes can
be assigned an amount of time. To do so, you must add a set of attributes to the
process and perform calculations that will allow you to display a partial time and a
total time. Moreover, you must include resources in your calculations, since resource
assignment to a process is also an element for which you can specify a period of
measurement. Here is an example on how to work with this feature. (Based on the sample model distributed with this product.)
- In the explorer window, right-click the 'Order Processing' process and choose Properties.
- Click in the Fixed Cost box, type in the process fixed cost (type in 15) and
press Enter.
- Click in the Fixed Time box, type in the process fixed time (type in 30) and
press Enter.
- Select Minutes as the time unit in the Fixed time unit box.
- Click Apply.
Once you have established the fixed cost and the fixed time for the 'Order Processing' process,
you can set up how much of a resource is used for a particular process (usage rates).
- From the same properties window, look for the Process / Resource tab.
- The Resource tab appears. Select 'Credit Manager'.
- Click in the box under the Usage Rate column and type in 10 and select
Hour in the combo box under the Usage Rate Time Unit column.
- For the 'Data Entry Clerk' type in 11 in the box under the Usage Rate
column and select Hour in the combo box under the Usage Rate Time Unit
column.
Now let’s look at a resource and see what the work load is. The work load is calculated
as the sum of all process usage rates for that resource.
- From the Explorer window, right-click 'Credit Manager' resource and choose Properties.
The work load indicated for the 'Credit Manager' is the sum of the all usage done for this resource in the model.
- Click in the box corresponding to the Cost, type in 20 for the resource cost
and select Hour as Cost Time Unit.
- Click Apply and Close.
- Repeat this step for 'Data Entry Clerk' but type in 15 for the resource cost
and select Hour as Cost Time Unit.
Now let’s take a look at a process and see what the resource cost is.
- Right-click the Order Execution process and choose Properties.
Note that the resource cost for the process is 365. This total is automatically calculated by
taking the cost of the 'Credit Manager' (20 x 10 hrs. = 200) and the cost of
the 'Data Entry Clerk' (15 x 11 hrs. = 165).
- Also note that you can assign a fixed cost which will be added to the calculated
resource cost to give you a partial cost. Total cost reflects all costs
from this diagram level and all costs from subprocesses for this process.
This gives a valuable overview of the business cost structure.
It is strongly advised that you learn the new attributes and time units
implemented as well as calculation rules and results described in the
rest of this section, in order to preserve your model integrity when you
modify the following time units: fixed time unit (process), usage rate time
unit (process-resource link) and cost time unit (resource). In most cases,
you can verify the accuracy of your calculations by accessing the Process
Description window. You can also produce and print a report including
all attributes involved in these calculations to detect inconsistencies
and to correct erroneous elements.
Time attributes
- Fixed Time: This attribute, like the Fixed Cost attribute, can be directly typed
in by the user. The fixed time represents a period of measurement value that
does not take into account the assignment time for resources nor the time
for processes included in the exploded process.
- Partial Time: The partial time represents the sum of the fixed time and the
resource time.
- Resource Time: This attribute represents the sum of time periods of all
process/resource links of a process. These time periods are defined in the
Usage Rate attribute.
- Total Time: The total time represents the sum of a process partial time and
its child total time periods.
Time units
Fixed Time, Partial Time, Resource Time and Total Time Units :
- Second, Minute, Hour: Values associated to this unit family are converted when the user modifies the current
unit.
- N/A: This “NULL” value is applied by default to earlier models to preserve data integrity.
The resources fixed costs are accumulated.
- Usage Rate Time Unit (Resource-Process Link):
This time unit applies to the existing Usage Rate (the time periods of a resource
linked to a process) attribute.
- Cost Time Unit (Resource):
This time unit applies to the existing attribute Cost.
- Work Load Time Unit (Resource):
This time unit applies to the Work Load attribute (the accumulated time of a resource
in the model).
Calculation and validation rules
Generally speaking, the validation is performed on time units when the corresponding
time value is different from 0.
Process
- Partial Time: Partial time is calculated if fixed time and resource time are
not null and if their time units belong to the same time unit family. Otherwise:
- Partial time = 0
- Partial time unit = n/a (null)
- Resource Time: Resource time is calculated only if all resources linked to
a process have the same time unit family associated to usage rates. Otherwise:
- Resource time = 0
- Resource time unit = n/a (null)
- Total Time: Total time is calculated only if all child processes and the current
partial time have the same time unit family. Otherwise:
- Current total time = 0
- Current total time unit = n/a (null)
- Resource Cost: Resource cost is calculated in two manners.
1. Variable cost - The result of usage rate and the resource cost if time units are the same.
2. Fixed cost - The addition of cost if the time unit of resource cost is NULL.
N.B. The cost of one resource is invalid and not calculated if time unit of usage rate is NULL and time unit of resource cost is not NULL.
The resource cost integrity can be verified if you produce a report relating to linked
resources and processes.
Resource
- Work Load : Work load is calculated only if all processes linked to a resource
have the same time unit family associated to usage rates. Otherwise:
- Work load = 0
- Work load time unit = n/a (null)