Costs

Costs

The cost tab allows you to create a cost risk model independent of or integrated with the schedule. It enables you to model costs and their associated uncertainties and risks. When the model is run together with a schedule, you get an integrated cost schedule risk analysis.

When you want to perform an integrated cost schedule risk analysis (ICSRA), the main idea is that the schedule drives the costs. This is achieved by connecting costs to activities in the schedule. The costs will then vary in proportion to the duration of the activities during the risk analysis.

An alternative way to do an ICSRA is to use the cost-loaded resources in the schedule tab. In Safran Risk, you must use either the schedule resource method or the cost tab. There's not currently a way to combine the two in any meaningful way.

When you use the cost tab for modeling costs, all the cost results in the output tabs can be found by clicking the Cost icon in the ribbon.

Activation

If your license key includes the Cost Module, you will see a "Cost" tab to the right of the "Schedule" tab. Please contact Safran Software Solutions Support if you don't see this tab and want to access the cost functionality.

Importing and Exporting

Excel

A Cost Breakdown Structure (CBS) can easily be imported from Excel. This is done by adding your costs to the Safran Risk Cost Import Template. To create a template, you can export an empty cost model.​

After you've opened the template in Excel, you can add your costs there in any way you like. This will result in an Excel document that looks like this:

Once you've added all your costs to the template, save it, return to Safran Risk, and click Import.

In Safran Risk, the costs will look like this:

You can also use the Excel import/export functionality to modify existing costs in Excel.

XML

If you'd like to move your costs from one Safran Risk project to another, using the export/import risk model functionality is recommended. The costs are part of the risk model. The export/import risk model functionality is situated on the Home tab.

When you export and import a risk model into another project, all the mappings between costs, risks, and activities will be maintained.

Grouping and Ordering of Costs

To group the costs, you need to add an outline structure. This is done by clicking the grouping button.

You use the Add, Remove, and Edit buttons in the Grouping dialog to create an outline. To edit the nodes' names, you can click Edit or double-click on the node. Changing the structure by dragging and dropping the nodes is also possible.

If you want to change the background color of the group heading, you can do this in the Format tab in the Grouping dialog.

All the costs are ordered and grouped as they are added. If you, for example, have selected a cost in a group and clicked "Add Cost," the new cost will be added to that group. You can move the costs around, inside or from one group to another, by drag and drop.

Integrating Cost and Schedule

The first part of integrating cost and schedule is getting schedule and costs into the same project. If you start with a schedule, adding costs should not pose a problem. You can add or import the costs from Excel or as part of a risk model XML file. If you start with a cost model and want to add a schedule, these are a couple of different methods you can use:

First method:

First method:

• Close down your project.

• From the Home tab, choose one of the import options.

• In the Project Import dialogue, select the project to which you would like to add the schedule.

• When you get to save, you will get the following dialog:

• Click ok. Only the schedule will be overwritten, not the costs.

• You should have both a schedule and costs for your project.

Second Method

• In the project with the costs, go to the home tab.

• Select "Export Risk Model". This will export your costs together with your risks to an XML file.

• Close down the project.

• Import the schedule into a new project.

• Go to the home tab and click "Import Risk Model."

• Please find the file you imported before and import it.

• You should now have a project with both a schedule and costs. You can now start integrating them!

The connection between Schedule and Cost is handled in the Schedule Connection section.

Here, you can let one or more activities drive costs. This connection can be turned on and off by clicking the check box in the first column of the schedule connection section.

To connect a cost to the schedule, select the check box and click the schedule button in the Activity column.

This displays the following dialog:

You can pick one or more activities that drive the cost in this dialog. You can set a fraction for each activity between 1 and 100%. This represents the part of the cost affected by a particular activity. During the risk analysis, the cost will change proportionally with the change in the duration of the activities. When the duration is longer than the deterministic, the cost will increase; when the duration is shorter than the deterministic, the cost will decrease.

The formula for this relationship that is used in each iteration during the risk analysis looks like this:

Example:

Base Cost: 1000

Fraction: 100%

Duration in Iteration: 150

Deterministic Duration: 100

If you're using fractions with multiple activities, the formula looks like this (Note that the sum of fractions can't be more than 100%).

Example with two activities (A and B) driving one cost:

Base Cost: 1000

Fraction of cost affected by activity A: 50%

Probabilistic Duration of activity A: 150 (longer than deterministic)

Deterministic Duration of Activity A: 100

Fraction of cost affected by activity B: 25%

Probabilistic Duration of activity B: 170 (shorter than deterministic)

Deterministic Duration of Activity B: 200

Mapping Risks to Costs

Some costs are affected by risks. This can be modeled by adding the risks in the Risks column.

In the risks column, you add the risk either by clicking the button, typing in the grid cell, or by clicking the button in the Risks tab in the Cost Element details section. Only the risks containing the typed characters will be shown when you type. To delete a mapping to a risk, you click the little X on the risk. You can also delete a risk mapping by deselecting it in the risk selection dialog and clicking ok.

The risks available in the cost tab are the ones that have been defined in the Project Risk tab with a cost impact.

You can see more details about the risk in the cost details window. To edit the risk, however, go to the Project Risk Tab.

Overriding the risk impact on Cost Element

In the risks tab in the details section, the risk impact can be overridden by checking the Override checkbox. This allows you to change a risk's impact on a particular activity. It works the same way when overriding risk impact in the Risk Mapping tab. For more information, see the Override section in the Risk Mapping chapter (Overriding Risks at activity level).

The order in which the risks impact one Cost Element is the following:

1. All relative in-series impacts are multiplied.
2. The parallel impact with the most significant effect (out of both the absolute and relative) is added.
3. All absolute in-series impacts are added.

A mathematical way of expressing this:

X: Deterministic or value from distribution if uncertainty defined
Irs: Relative in series impacts
Ias: Absolute in series impacts
Irp: Relative in parallel impacts
Iap: Absolute in parallel impacts

Input Fields

Sometimes, it is desirable to model costs as a function of values in multiple columns. For example, you might want one column called Unit Price with the price per unit and one called Quantity, where you can enter a number of units. This can be achieved in Safran Risk by using Input Fields.

IIn the Input Fields dialog, you can add any number of Input Fields. The fields will be displayed as columns in the cost tab. You will automatically get an extra column called Total when you have more than one field. This column will display the results of the other fields. The Total value is, by default, calculated as the product of the fields, but this can be changed in the formula file at the bottom of the Input Fields dialog.

The Total value will be used when the cost element is affected by a Schedule Connection or Risks.

You can add two types of Input Fields, Actual and Remaining. Actual fields can't have any uncertainty, and their value can be excluded from the results after the analysis. The value of an actual field will always be added to the Total. Note that the Actual part of the total won't be affected by Risks or the schedule connection.

Formulas and Variables

Instead of just typing in a value, Safran Risk allows you to calculate the cost based on variables, durations from the schedule, and other costs or cost groups. Variables can be useful if you want to include variation from common factors in the risk model. You can, for example, create variables for the weight of an oil platform or an exchange rate and let many costs be based on these values.

Creating a variable

To create a variable, you click on the Variables icon:

This will display the following dialog:

You can create the variables you want to base your cost calculations on here. Each variable has a base value that can vary according to a defined base uncertainty.

Calculating a value using a formula

To calculate the value, select the cost and the "Formulas" tab in the cost details panel.

Here, you add the references (variables, activities, or other costs) you would like to base your calculation on. You can give your references a symbol that you use in the formula. For an example, see the screenshot above. Note that you can have a formula for each input field.

The Formula Editor

The formula editor allows you to do advanced calculations based on the references you've chosen. In addition to standard operators, it supports the following functions:

Example 1: Modeling a penalty:

Formula: Max(0, Days(Date(2019,2,15), [00010.EarlyFinish])) * Pen

This model shows a penalty incurred if the activity with ID 00010 finishes after 15 February 2019. The penalty day rate is taken from a variable given the Symbol "Pen."

Example 2: Modeling an overhead cost

Formula: 0.05 * Labor

This formula references the cost of a group of cost elements. This cost is multiplied by 0.05 to get 1 % of the cost. Note that if you use a decimal value in the formula, you must always use "." as a decimal separator.