How Companies Can Manage Spreadsheet Risk [Part 2 of 4]

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This series of articles will give you an overview of how to manage spreadsheet risk. These articles are written by Myles Arnott from Excel Audit

Introduction to Spreadsheet Risk Management

In the first article in this series we highlighted the risks that poorly managed spreadsheet solutions can introduce to a business. In this article we will demonstrate how companies can manage this risk.

A formal governance framework

The first, and arguably most important step is to ensure that the senior management team buy into the need for a robust spreadsheet risk management framework, and that they define and effectively communicate their spreadsheet risk management policy.

Spreadsheets identified and catalogued

It is impossible to know the level of spreadsheet risk in an organization without first identifying and then risk assessing all of the spreadsheets. It is therefore necessary to create a catalog of all of the spreadsheets and then to gather the key information about each spreadsheet to enable a risk assessment to be carried out.

The two key factors for determining the spreadsheet risk are the probability of there being an error and the impact that that error could have.

Risk = Probability of an error  X  impact if an error were to occur

The probability of error is related to the complexity of the spreadsheet. Complexity attributes differ across companies but include:

  • Spreadsheet size (Mbs)
  • Spreadsheet design (hard coded numbers in formulae, poor model structuring etc)
  • The number of users
  • The use of complex formulae (particularly array formulae, nested formulae etc)
  • The number of cells populated
  • The number of internal and external links
  • The use of VBA

The impact of the error is related to how critical the spreadsheet is within the business. Each company will have a slightly different definition of the impact levels of spreadsheets, but generally:

  • A spreadsheet is low impact if it is not used as part of a critical business process and an error would not have a material impact on the business.
  • A spreadsheet is medium impact if it contains confidential information and an error could have a material impact on the business.
  • A spreadsheet is high impact if it contains highly confidential information and an error would have a significant impact on the business. Spreadsheets used within processes that fall under external regulation (such as Sarbanes-Oxley and Solvency II) are deemed to be of high impact.

Finally, the spreadsheets should be placed in order of risk. Those identified as business critical and high risk should be prioritized for detailed review and placed under control.

This is clearly an on-going process. As new spreadsheets are developed they will need to pass through the risk assessment process as defined by the company’s spreadsheet risk management policy. A periodic review should also be carried out to ensure that all spreadsheets have been correctly categorized.

A best practice standard

The company should define its own best practice spreadsheet development standard that is applied to spreadsheets deemed to be medium or high impact. The standard should clearly outline the standards and conventions to which a spreadsheet should be built. New developments can then be reviewed to ensure that they adhere to the standard.

We advocate the use of the Excel Best Practice Standard from the Spreadsheet Standards Review Board (‘SSRB’).

We also recommend that tailored schedules are added to the standard to reflect your specific design standards. For example this could be a specific color scheme, use of logo or the use of specific text within the header or footer (e.g. document security levels).

Testing

A fundamental, but often overlooked step in the Excel model development cycle is testing. All spreadsheets (but especially business critical spreadsheets) need to be first peer reviewed and then rigorously tested.

It helps to consider the steps that an IT department would take to ensure that something they deliver is correct. It will pass through stages of unit and system testing prior to quality assurance and finally user acceptance testing. So why should a spreadsheet being used for a critical process be any different?

The fact is that no matter how hard we try, humans make errors. The purpose of testing is to identify them and get them resolved before the model goes into the live environment.

Remember that in the first article we highlighted the fact that 94% of spreadsheets and 5% of all formulae within spreadsheets contain errors.

Here is Scott Adams’ view on spreadsheet testing in Dilbert

 

 

Training

All staff should be trained so that they have sufficient Excel knowledge for their role and to use the spreadsheets that they are responsible for. As part of the induction process all staff should also be taught the company’s best practice standard.

Whilst this sounds obvious, research has shown that few companies prioritize investment in spreadsheet training.

 

Documentation

A key risk with spreadsheets is that they are often built and used by one individual within a team (often referred to as a “key man dependency”). If this person is ill or leaves unexpectedly the other members are totally reliant on the documentation left behind. From experience this rarely exists.

Each spreadsheet that is used within a process should as a bare minimum have documentation stating:

  • the purpose of the spreadsheet;
  • how the spreadsheet fits within the process;
  • the source of all inputs for the spreadsheet;
  • all key assumptions and drivers;
  • key calculations;
  • distribution list for outputs.

Spreadsheets that are part of as critical business process should have detailed documentation. This should include a technical specification and user notes.

 

Security

All business critical and confidential spreadsheets should be subject to access control. Security controls can be implemented across three levels:

  • Directory level: Only specific individuals have access to key directories
  • File level: Confidential and critical spreadsheets should be password protected to restrict access
  • Cell level: Non-input cells should be password protected

 

Change control, backups and archives

To minimize the risk of losing the current version of a spreadsheet and ensuring that the correct version is being used at all times, all business critical spreadsheets should be backed up, archived and subject to change control procedures.


So, in summary..,

the characteristics of a well-managed environment are:

  • a formal governance framework, sponsored by the senior management team, is in place for all spreadsheet development;
  • a catalog of spreadsheets is maintained and prioritized by risk profile;
  • a best practice standard is applied to the development of all new spreadsheets;
  • all new spreadsheets pass through a formal risk assessment, are peer reviewed and formally tested;
  • staff are provided with sufficient training to carry out their roles;
  • all spreadsheets and their associated processes are well documented;
  • access to critical spreadsheets is subject to security controls;
  • spreadsheets are subject to change control and are regularly backed up and archived.

What next?

In the next article we will look at the built in Excel functions that can help you to manage spreadsheet risk.

What about you?

How do you (or your company) manage spreadsheet risk? What best practices & guidelines you follow? Please share using comments.

Thank you Myles

Many thanks to Myles for writing this series. Your experience in this area is invaluable. If you enjoy this series, drop a note of thanks to Myles thru comments. You can also reach him at Excel Audit or his linkedin profile.

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15 Responses to “Modeling Interest During Construction (IDC) – Excel Project Finance”

  1. Terry says:

    Thanks again for a very helpful post.
    I had a similar problem when trying to model a balance sheet and profit and loss projection. The problem was that interest expense (in P&L) was dependent on a cash shortfall (in BS) which had to be funded. The cash shortfall depended on how much interest was paid, so the mutual dependency made a circular reference.
    I addressed it with a macro that calculated interest outside of the P&L, then pasted the calculated amount into the P&L as a value. The model was out of balance, but by repeating the pasting and calculating loop the imbalance reduced to zero. It was a bit messy, and had to be repeated every time a line changed - but it worked.
    If I have to do it again I'll read this article again first and see if it can be done more elegantly.

  2. Tristan says:

    Hi,

    The use of a circular reference can be avoided in this case. Just make use of the geometric sum to calculate the interest required. I’ll walk through the example from the spreadsheet.
    First calculate the cash needed each year without the interest expense. So you year 1 you need 55 Mn, year 2 105 Mn, and 190 Mn for year 3. The total amount to borrow for year 1 is then (50 Mn)/(1-interest_rate) = (50)/(1-0.1). For years 2 and subsequent the amount borrowed is the cash needed in that year plus the interest_rate times the amount already borrowed. For year 2 (105 + interest_rate * sum(previous debt raised))/(1-interest_rate)=(105+0.1*61.1)/(1-0.1).
    This process avoids the need for a circular reference, and makes the calculation more stable.

    Thanks,
    Tristan

    • Suneel says:

      The question is for the year 1 in your case, the amount works out to 45 mn. However in the year 2 you have applied the loan amount as 61.1 mn.

      Am I missing something ! Please help !

  3. Yogesh P says:

    very helpful information!!!

    using circular references and to make model more stable we can use combination of "IF" and "ISERROR" functions. i.e
    =if(iserror(formula1),"",(formula1))

    this formula will return blank value if there is any error otherwise give the result required.

    I usually use this in my models and it makes them very stable......

    🙂 🙂 🙂

  4. @Terry: Thats right. Exactly same problem is seen in Interest - Cash cycle in P&L and Cash Flow statement as well. In our trainings on financial modeling in excel, we demonstrate using both the circular loops as well as the macros to take care of this problem. Circular loops have their own pitfalls. If the model enters into a state of error, the error percolates!
    @Tristan: Thanks for pointing out. I agree with you that if circular loops can be avoided, they should be avoided.
    @Yogesh: This is one way of avoiding the problem. Although circular loops have another problem that they make your sheet slower. Each time, there is a change in the sheet, all the calculations are redone. So if they can be avoided, they should be avoided.

    Please note that this was an example (a large one indeed) and I didn't have space to speak about the pitfalls of this approach! I just wanted to illustrate an approach and am glad that some of you found it useful!

  5. I think while posting, there is an error in the images! The last image should be flipped with the one that is posted in step VII!

  6. MarselR says:

    I think you can try the following simple solution given by Microsoft itself to make the circular works:

    Windows: Excel Options -> Formulas -> Put a tick on "Enable iterative calculation"
    Mac: Excel -> Preference -> Calculation ->Put a tick on "Limit iteration"

    You can change the maximum number of calculation iterations as well as the maximum changes which iteration stops for goal seeking or for resolving circular references based on the number you type in the maximum change box.

    Thank you.

  7. Vinay says:

    Hey All

    I heard that we can take care of the circularity with the help of macro for IDC. Can anybody help on the steps to construct the macro for the same.

    Regards
    Vinay

    • Hi Vinay,
      If you look closely, you are essentially copying the values from the interest calculation to the IDC in project cost.
      Basically you can record a macro, that takes the values from interest and pastes special the values in IDC row in project cost.
      Then you can run that recorded code in a for loop.

      Hope this helps.

      • Vinay says:

        Thanks Param for reply.

        But before calculating interest, i need to provide for Upfront Equity and Equity, which are essentially part of total project cost. Hence, i need to put in Upfront Equity and Equity to calculate the IDC which is again hitting the total project cost.

        Bit of confused on how to remove this circular reference.

        Regards
        Vinay

  8. M says:

    Wow, this was a brilliantly simple post. I was looking online for a while before I found this page. Never seen this been explained so beautifully yet so crisply before. Thanks for saving my ass at work! (i'm relatively new to finance + modeling)
     

  9. áo s? mi nam hàn qu?c ? hà n?i says:

    I'm not sure why but this web site is loading very slow for
    me. Is anyone else having this issue or is it a problem on my end?
    I'll check back later and see if the problem still exists.

  10. Pravin Khetan says:

    I have been reading your blog since my college days. Today, I'm writing just to say thanks.

  11. Engr. Fida Hussain says:

    We have calculated Financial Rate of return of a hydropower projects, and the observer has raised an observation regarding Total Project cost with IDC Rs. 8616.01 million (PKR) and with-out IDC 8352.46 million (PKR). How does the Financial nalysis be calculated on the basis of with-out IDC Or With IDC?????
    Please helpf. if possible to spare some time.

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