Tag Archive | Cost estimation

Algebra in management accounting

Many years ago when I work in an accounting practice, we had a client who kept no wage records for a while. All we had was the net pay of each employee. We needed to get the gross pay, as well as the tax and social insurance, to do proper accounts and sort out the taxes owed. Back then we had no software to do this. So what did we do?

Well, we used algebra. We knew tax and social insurance rates and these were all a percentage of gross pay. We ended up with something like this :

G – 0.20G – 0.07G= Net

So we solved for G. It’s a bit more complicated today as back then the social insurance was a flat rate – and what I show above is only illustrative. What made me think about this past experience was a CIMA post about how we still use algebra in many management accounting tasks today – read more here.


Another cost-volume-profit example – supersize portions

English: A Big Mac combo meal with French frie...

In June this year, I was watching a programme called “The men who made us eat more” on BBC. It told the story of how super-size portions and combo-meals came about in fast-food chains like McDonalds, Burger King and other similar ones. One of the participants mentioned how the profit margin on the extra portion (or the additional products in a combo-meal) is huge. He explained why, and the explanation is again an application of understanding costs and volumes (or CVP).

Let’s take the example of a portion of  french fries.  If we think about the cost of a regular size portion first. The variable cost would be mainly the ingredients,  i.e. potato, packaging cost and maybe energy costs. There would be quite a few fixed costs – all the costs associated with the running of the restaurant, including staff costs (they need to be paid even if there are no food orders).  Now if we make the portion size larger, the additional cost will be very small – some extra ingredients, a slightly bigger package and that’s about it.  But, the price increase is proportionately much higher than the cost increase usually. Thus, by encouraging a customer to super-size or buy a combo-deal,  profits can rise at a much faster rate than the corresponding increase in costs.

A cost-volume-profit-example – a child care facility

The BRiC charging

The BRiC charging (Photo credit: fe2cruz)

In this and the next post, I will give you two simple examples of cost-volume-profit (CVP) analysis in action. CVP analysis, or sometimes it’s called break-even analysis, is a useful decision tool for any business to understand effects of cost changes or sales volume changes on underlying profit.

The first example relates to small Montessori school run by someone I know. In Ireland, preschool children get some free childcare and the owner of the facility gets paid €250 per child per month. The Montessori in question is insured to have 11 children with one staff member, but beyond this a second employee is needed. The full capacity of the school is 15 children and the extra employee costs €620 per month. This is a fixed cost. If you do some quick calculations, you can see that it takes 3 children (€ 750) to cover the employee cost. Thus, the owner needs to have 11 or less children with one employee, or 14 or more with two employees. So you can see how the fixed cost increase affects the volume needed to keep profit levels stable. There may of course be some additional variable costs with more children, but I am ignoring these to keep the example simple.

What is a “business model”?

Often, when I teach about types and classifications of cost in my management accounting classes, I use the term business model. For example, I might say “whether a cost is fixed or variable, can depend on the particular business model”. But, I am assuming the term business model is well understood. Perhaps it is not, and even when I asked myself what the term means,  I had to do a bit of thinking. So here’s a simplified explanation.

An article in the Harvard Business Review from 2002 describes a business model as “the story which explains how an enterprise works”. This is a deceptively simple definition, but it does capture exactly what a business model is. If I were to ask you what are the essential elements of a story such a Cinderella or The Frog Prince, you would probably says things like characters, what the characters do, when the characters do things, and of course the (moss likely) happy outcome. Using the story analogy, a business needs to ask itself, what is that we do, who are our customers, how much does what we do cost, and will we make money (the happy outcome!). In other words, “what’s our story”  in an economic sense (Read the full HBR article for more detail and examples).

Nowadays, business models have become a bit blurred though. For example, there are so many web-based “businesses” out there who, to be honest, do not immediately show a story which makes economic sense. For example, we now know how Google and Facebook can make money on a business model which changed the advertising world.  But, what about for example Twitter or off-shoots like paper.li. I love the latter, as I can bundle all the twitter users I follow into a daily newspaper, but how can this make money. I am guessing they will introduce advertising, but has this business model already been over-cooked?

I hope this helps you understand what a business model is. To conclude, I suppose the story of what it is a business does has to be infused with accounting concepts. For example, there is not point being the world’s best at something, but costing a fortune to do it.

Using Microsoft Excel to estimate costs with linear regression

If you have studied management accounting, you may remember the long-winded formulae to estimate values to put in a linear equation. Well, it’s a lot easier using MS Excel. Take a look at this video I have put together.

Estimating costs using multiple regression analysis in Microsoft Excel

I am writing a management accounting text book chapter at the moment and put together a short video on how to get Excel (2007) to do multiple regression.  The multiple regression technique is often used to estimate costs that are influenced by several factors. Click here too see the video. Hope it helps

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