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6 business terms you should know before your case interview

Team Prosple

Don't have a business background but want to work in consulting? Read our guide of 6 key terms you must know before your consulting case interview.

If you’re a graduate chasing a career in consulting, chances are you’ll come across a case interview. Case interviews allow you to demonstrate how you think - your ability to understand a problem, break it down into its requisite parts, analyse them and communicate a solution. Check out Case Interview 101 to find out more about what a case interview is and seven tips on what to do in a consulting case interview. Right now, it’s time for you to get familiar with these six business terms that you absolutely must know before your case interview.

Things to know

It’s important to remember that consultants come from all different walks of life. And by that, what we mean to say is that not everyone has a business background. So, if you don’t have a commerce, business, finance, accounting or strategy degree, never fear! Consulting is about logical, rational and analytical thinking with creative flair.

However, it is worth understanding a few fundamental business basics so you’re not resorting to ‘Please Explain’ throughout the entire case interview. So, here is our quick ‘Business 101’ guide to ‘things you ought to know.’


When we talk about revenue, what we are referring to is the amount of money a company makes. At its simplest, revenue is calculated by multiplying the price at which goods and services are sold by the number of units or amount sold within a time period. For example, say a coffee shop makes 100 coffees a day and sells them each for $3. The revenue that the coffee shop makes is, therefore, $300 a day. Over a year their revenue would be $109, 500. This assumes of course, they sell the same number of coffees every single day for the entire year.

As you can see, there are two ‘levers’ of revenue here – the price and volume sold. If a business wanted to increase its revenue, it may consider either raising its price, attracting new customers or increasing the number of coffees bought by existing customers. It may do a combination of all these things.

Often a business will have more than one type of revenue stream. In our coffee example, the coffee shop may also make money by selling food, catering for lunches at nearby offices or displaying art for sale on its walls. In consulting speak, we call these ‘revenue drivers’. Typically, you will find that one driver is more dominant than another.

You will often hear revenue called the ‘top line’ or ‘gross income’ figure. This is because it is the amount of money that the company receives during a specific period. It does not take into account the costs of running the business itself.

Applying revenue to the case interview

It is common during the case interview to consider how a business might make money. After all, this is what a business is set up to do! Whether an organisation is seeking to launch a new product or service, enter a new industry or geographic market, it must consider how it will generate revenue.

As a consultant-to-be, you will be making a number of assumptions about how the business operates. In our coffee shop example, we assumed that the number of coffees sold every day remained the same. Would this really be true in real-life? It’s here that you can have a bit of fun and apply some logical thinking. For example, a coffee shop that’s in the middle of the CBD may be busiest during the week compared to the weekends or over the Christmas break.

The opposite may be true for a coffee shop on the beach. When making assumptions be careful about what it is you are actually assuming and be sure to take a step back and look at the bigger picture. At the same time, don’t over complicate things. If you need to make a simplifying assumption so that you can move on, that’s perfectly ok. Just state that you are doing exactly that and check in with your interviewer.

A good way to practice ahead of the case is to think about organisations you interact with regularly and ask yourself, ‘How does this business make money?’. Whether that is your local coffee shop down the road, or companies such as Spotify, Telstra, Westfield or Google, consider what their different revenue drivers might be.

Spotify, a digital music service, for example, allows users to stream music for free if they are willing to listen to advertisements, alternatively, they offer users a subscription fee for a premium service. If you were given a company like Spotify during a case interview, you may be asked to estimate their revenue. You would need to make assumptions for example about how many users they have, what proportion of users are free vs. paid, how much it costs to subscribe, the different rates of subscription (e.g., student vs. regular vs. family accounts), how many advertisers they have and what their advertising rates are.

See if you can break down each of these assumptions in a logical way to come up with a final revenue number – and then see how it compares to the real-life thing! Don’t forget, it’s not about the ‘right’ number, it’s about the thinking process.  


Expenses refer to the costs of running a business. They are the opposite of revenue. For example, for our coffee shop to make its coffees it must buy all the materials required including coffee beans, milk and sugar. The coffee shop must also pay its employees to make the coffee and serve customers.

Expenses may be further divided into fixed and variable costs. Fixed costs refer to those which are independent to output – that is, no matter how many coffees our coffee shop makes, the shop must still pay rent (a fixed amount), the lease of the coffee machine and other equipment.

In contrast, variable costs refer to those that do vary with output. For example, the more coffees we make, the more coffee beans, milk and sugar we will need to buy. Similarly, if the coffee shop grows and as a result, we make more coffees, we will also likely have to hire more staff.

Applying expenses to the case interview

Just like revenue, when you’re practising for the case interview, consider what’s going on the ‘other side’ i.e. what types of costs that business may be incurring. In our Spotify example, costs include streaming, music licensing and royalties, hosting, product development, sales and marketing and employee wages. For each of these you would need to come up with a logical explanation of what these costs may be and be able to justify your assumptions.

Let’s work through the potential streaming costs, as an example. What do we need to know to make these calculations?

First, we need to consider how long an average user listens to Spotify every day. Well, the average user may listen to Spotify part of the way to/from work or school, and perhaps a little bit during their day. As a conservative estimate, we can assume that this is about an hour a day.

We may then ask ourselves, what does this actually mean in terms of streaming? You may not know anything about streaming and it is ok at this point to ask the interviewer for some guidance. Suppose the interviewer tells you that streaming is in kilobits per second and that an average user would stream 160 kilobits per second.

This means we can then calculate per user that they are streaming 160*60*60 = 576, 000 kilobits per day. The interviewer at this point may suggest we convert this to megabytes, indicating that 1 kilobit =0.000125 megabytes (MB). Once we crunch the numbers, we will find that per user, they are streaming 72MB per day.

We then need to make some assumptions about how many Spotify users there are in total. After some guesswork about countries that Spotify is in and what proportion of the country would have access to the Internet and be of the demographic that would listen to Spotify, we may come up with a total of about 100 million give or take. (Actually, the latest we heard was that the number of Spotify active users is actually much higher and more around the 150 million mark but for simplicity, we’ll go with 100 million).  

If we assume that all these users are listening for an hour per day, that’s 100 million users x 72MB = 7.2 billion MB per day or 7.2 million GB per day of streamed day (where 1MB = 0.001 GB).

To continue with estimating the streaming costs, we would then have to find out how much it would cost to stream per GB. Again, you are not expected to be familiar with streaming so you may ask for guidance at this point. Let’s say we find out that it costs about $0.10 per GB. So, 7.2 million*0.10 = $720, 000 per day in streaming costs.  

Now, we basically pulled these numbers out of a hat and have no idea if this is actually correct or not. The point is, it doesn’t matter. So long as along the way we have justified each assumption to the satisfaction of ourselves and the interviewer, then the end number doesn’t really matt