I just posted an extensive answer to an identical question, but let me repeat it here. First of all - doing isolated “drills” for chart interpretation like offered on Rocket Blocks is a COLOSSAL waste of time! It is IMPOSSIBLE to practice this in an isolated manner, since you will NEVER be able to gnerate an insight just by looking at a chart! The keyword is CONTEXTUALIZATION! Please refer to point 4 below!
Effectively interpreting data and information is one of the crucial success factors in most case interviews. Very often, this data comes in the form of graphs or charts which the interviewer shares with the candidate at some point during the case. Finding the central insight of the chart, the ‘so-what’, is the single most important quality you will have to show in this situation!
There are a few habits which, if properly internalized and applied, will massively help you to impress the interviewer in this domain! Let’s go through them one by one…
1 Take TIME!
The first thing you should do when presented with a table or chart is to take time to properly scan the information provided. In fact, you should ideally have a “standard phrase” such as
“Thank you! I see, there is quite some information on this chart. So let me take a brief moment to quickly scan the information and identify…
which steps we need to take to determine X” (if the interviewer has asked you a concrete question like “How to derive XYZ from this data?”)
…how we should proceed” (if the interviewer just gave you the chart but asked for no concrete analysis)
This is a very frequent Achilles’ heel with candidates! It is a pretty widespread problem that candidates tend to put themselves under time pressure and start talking before even having properly looked at the chart! The consequence is that you are not crisp in your messages, you’re just “wobbling around”, starting sentences without knowing how you will actually end them, etc. This leaves a very bad impression! Interviewers at MBB actually TEST for whether you have the maturity to take the space that you need in order to conduct a proper analysis! Just understand it from the interviewer’s perspective: as a project manager, the last thing I want to have on my team is a young colleague who tends to talk before thinking! This would represent an enormous risk in client interactions and can undermine credibility of the whole team, or even the whole firm!
What leaves a much better impression is to confidently announce that you will need a moment to
- take in all the information on this chart,
- link it to what has been discussed to this point,
- suggest the best way forward.
Another reason for taking time is that it allows you to verify/clarify your understanding of the information given. Very often, e.g. unit abbreviations are not entirely clear (or even lacking!). Taking a moment after receiving the chart will allow you to scan these elements and clarify their meaning with the interviewer, before you start discussing observations and insights.
2 Scan the base parameters (“Read the chart correctly!”)
This is tightly related to the previous point of taking adequate time. Oftentimes, candidates do not pay attention to what is actually shown on a chart, hence they are not properly grasping the parameters and what they actually describe! A couple of habits are important when reading a data table or chart.
- It starts with reading the title (this sounds trivial, but oftentimes just properly reading the chart title would have prevented candidates from stating obvious nonsense!)
- Look at the units and labels (frequent source of misreading charts!)
- Identify whether and which dependencies are shown on the chart (just properly checking what depends on what is oftentimes a very effective way of preventing yourself from completely unnecessary instances of misreading data! For example, in a x-y-axis chart, the vertical metric (y-axis) usually depends on the horizontal metric (the x-axis), and NOT the other way round!)
3 Identify key observations
The key messages (the ones that are relevant for the client’s question) within data and charts are usually found amongst the following:
- Static relations
Let’s look at each of these points.
- Static relations
- A simple comparison of values (comparing one number or group of numbers to the others - often a bar or a line chart), e.g.,
- comparing client metric vs. market average or vs. competitor (e.g., “Client’s profit margin is 30% below strongest competitor.”)
- comparing one scenario vs. another scenario (e.g., “Outsourcing is 20% cheaper than in-house production.”)
- Specific number or group of numbers showing growth or decline (e.g., “Revenue has grown by about 10% over the last three years, however profits have halved during that time frame.”)
- Rate of change compared to other logically related numbers (e.g., “Sales volume drops by 20% for every 10% increase in price.”)
- Specific relationships between two or more numbers; such correlation can be geared towards the same direction (positive correlation) or in divergent direction (negative correlation)
- Pretty often, even if Totals seem to show a consistent pattern, digging deeper into specific segments will reveal certain “hidden shifts”
Spotting those kinds of patterns quickly is vital. When you are given two or more charts, the key message usually becomes evident by combining them. Again, here you might need to take appropriate time.
4 Turn observations into insights & avoid “spontaneous amnesia”!
This is a BIG one!
One of the most amazing observations I have made over the last couple of years is the following. Many candidates, as soon as they get a chart or data table, fall victim to what you can call “spontaneous amnesia”! This means, they immediately forget EVERYTHING that has been discussed leading up to this chart.
Instead, they tend to stare at the chart, drowning in the information, and trying to distill insights JUST by looking at all the information on the chart. But they DON’T CONTEXTUALIZE the chart! This means, they don’t relate the information on the chart back to the core question, the criterion to answer this core question, or to the last insight generated BEFORE the chart was given out by the interviewer.
So, there is a simple trick: as soon as you receive a chart or data, your IMMEDIATE mental reaction should be “Wait, what did we just discuss, that led the interviewer to give me this data now?”. Usually, this is often sufficient to point you to the central insight of the chart!
You must be guided by the LOGIC which allows you to answer the core question, and the chart should just work as a source of information to perform the required corresponding analyses.
!!! Do not be guided by the chart itself !!!
Because very often, not all information on graphs you get is insightful or important! Parts of the information in the charts are crucial, others just create noise to distract you. Taking your LOGIC as the guiding star will allow you to quickly identify which pieces of information are crucial to generate the required insights to proceed towards an answer to the client question.
5 Communicate top-down and propose next steps
Whenever you present an insight during a case interview you should communicate your findings top-down. The same is true when presenting your interpretation of a chart, table, graph, etc. Start with the single most important fact you can extract from the chart.
- Communicate this key insight that you identified from the chart
- Then, give the reasons for your conclusion. These reasons must be substantiated by the data!
- Based on the insight generated, proactively suggest (without having been asked by the interviewer) the logical next step in your navigation through the case in order to proceed towards reaching a recommendation/answer for the client!
All of these points are vital to understand and master. Unfortunately, it is very difficult to do this on your own. You will need senior guidance for this, otherwise it will inevitably take quite long until you really reach excellence here. Just like on the job - adequate mentorship ensures swift progress. Trying to figure out curcial skills on your own will take a lot of time. And time is very expensive - much more expensive than cash usually...