Chart and Graph Reading

Anonymous D asked on Jul 15, 2018 - 22 answers

Hi,

what are some good resources to improve charts and graph interpretation/reading?

Thanks

22 answers

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Anonymous replied on Jul 19, 2016

A little late for this question, but thought I give it a shot, since I use charts in my cases often.

What's the biggest mistake I see? Looking for patterns in values. To give an example: Let's say, I show a simple bar chart for an white goods company, depicting fluctuating sales numbers (in units) for refrigerators and washing machines from 2000-2015. Very often, candidates come up with answers like this: "One can see that sales overall were very flat over time, average probably 300,000 units a year, except for the big drop in 2009, maybe because of the financial crisis. Interestingly the share of washing machines is quite constant at 60% of units over time".

Why is this bad?

  • No insight - it's from the stating the obvious department. The candidate explains to people who are responsible for these numbers as their main job HOW these exact numbers LOOK to an outsider. Believe me, they know.
  • Wild accusation (financial crisis). (don't confuse with business judgment!) [This always amuses me, I just update my case charts by 1 year each year, and candidates try to connect the data to historic events]
  • It's out of context, no idea why the candidate is doing what he's doing or where he's heading (assuming the chart is part of a case and not the exercise itself)

It's obvious that candidates have no clue what to do, but this is the worst way to buy time. OK, since you asked, how SHOULD you do it?

Key elements of any chart are: Title, axes descriptions (units!!), and legend. The values are far, far less important, in the end they only go into the equations. My favorite approach:

  1. Say title, axes descriptions with units, and legend out loud. Medium to slow tempo to buy thinking time.
  2. Connect it to whatever the hell you were doing BEFORE you got totally confused by the chart. If necessary, repeat what you are aiming for at this point in the case structure.
  3. Pick the elements/numbers from the chart you actually really need for 2. Chances are, a large chunk of the data is completely useless. Making sense out of a mess is a core consulting skill and tested for in interviews.
  4. Continue with the case to the next point.

How would a good answer look like? "On this chart, I see the sales number of refrigerators and washing machines from 2000-2015 for the client in thousand units. In order to now estimate the sales potential for the new detergent line as add on, I need to estimate the number of washing machines of our client's brand in households. I would thus take the sales numbers from ..."

--> Repetition buys time and brings clarity (= shows your understanding to the interviewer, and thus your listening skills), and is not "wrong". Repeating the "why" shows you're in control and managing the situation, heading to solve the case.

This is a trick consultants use all the time: Repeat facts or repeat the overall goal. :) For steps 1 and 2, you don't yet need to think AT ALL, bring any prior knowledge, or even understand the chart. And you still sound smart and have a bit more time to figure things out.

Hope this helps, good luck for the interviews!

Francesco
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updated his answer on Jul 16, 2018
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Hi Anonymous,

As a general first step, before every graph analysis it is important to ask for time to be able to read it.

After you took some time you should proceed with the following.

How to read charts and graphs in Case Interview

  1. Summarize what the graph is about. Read in particular the graph title (often forgot), the axes and the legend.
  2. Restate the main question you have to answer. Many people don’t spend the time to clarify the specific question they have to answer; consequently, they end answering the wrong one. Don’t be one of them and be sure to restate what is the main insight you have to derive
  3. Provide an analysis related to the question. Once you have the graph crystal clear as for the content, then, and only then, you can move to an analysis of how the graph can answer to the question you have restated.
  4. Provide a conclusion for the graph that answers the original question. Again, very often people simply state what the graph is about, without providing any conclusion. A great candidates will provide a connection between the analysis done and the previous question formulated, with a clear summary for the whole analysis
  5. Present the next steps to follow based on such conclusion. As a last step, a great candidate will present what can be done as additional steps to help further the client on the particular question raised.

Best,

Francesco

(edited)

Vlad
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replied on Jul 15, 2018
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Hi,

You can use the following approach:

  1. Take a minute to look at the graph
  2. Read the graph title
  3. Look at the graph type and define the type (pie chart, line chart, etc)
  4. Look at the legend (ask for clarifying questions if necessary)
  5. Identify whats going on on the graph. Look for: Trends, % structures,
  6. Look for unusual things - correlations, outliers,
  7. Make 3-4 conclusions from the graph. Think of potential hypothesis on what could be the root cause / what are the consequences
  8. Prioritize the most important for your current analysis and move forward with the case

Sources to learn from (prioritized):

  1. Study "Say it with Charts" book by Barbara Minto
  2. Learn basic statistics (Any GMAT or MBA prep guides)
  3. Check all available MBB presentations and publications. Practice to derive conclusions and check yourself with the actual ones from the article / presentation
  4. GMAT IR part (Official guide and Manhattan prep)
  5. "Consulting Bible" and "Vault guide for consulting" - check the chapters on cases with graphs in these books

Good luck!

Hemant
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replied on Jul 06, 2018
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Mckinsey way:

- first read "around the chart" then "into" it. Lots of context for the data is written around the graph.

- focus on "insights". Whenever I show a graph to someone where the profits were growing from yr1-5 and falling from yr5-7 but margins were falling much faster from yr5-7, and if they come back repeat that same info to me, they get rejected in my book. I can SEE the graph, tell me something DEEPER. For example, tell me that margins falling faster than revenue is likely because it's a fixed cost heavy biz.

- get good at narrowing down what you want to focus on in the graph. If your case is about P&L, focus on finding about profits, costs, F & Var costs, etc. Do not over-rotate on margins/profitability. Do NOT waste time trying to mentally calculate margins fell by 22.67% in year 2-4 -- it may impress the interviewer but not at the cost of you actually telling her something that takes the case fwd!

Hemant

Dorothea
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replied on Jul 05, 2018
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Hi Anonymous,

I assume you are referring to chart reading in general and not to any specific types of charts.

In general, your interviewer may ask you to read a chart and interpret it in a consulting interview. These may be all types of charts, hence you should be familiar with the basics of chart reading. The key here is always to

  1. describe what you see: think aloud while trying to understand the chart. Thereby your interviewer will be able to follow your thought process
  2. contextualize the chart: put the chart into the overall case context - what was the main question? How does the chart fit it? Does it change any of your assumptions?
  3. interpret: interpret what you see and how it fits with the context. What implications may this have to the overall case? It makes sense to state some initial hypotheses. If there are numbers on the chart, use these numbers to quantify your hypotheses and to show your interviewer that you already think one step ahead.

There is a good tutorial on preplounge that explains the steps I just explained in more detail.

https://www.preplounge.com/de/bootcamp.php/case-cracking-toolbox/practice-your-basics/how-to-read-charts-and-data-in-case-interviews

Best

Dorothea

Markus replied on Jul 05, 2016

Hi, there's a Case in Point Graph Analysis book (there should be more traps hidden in their graphs, they are rather plain) and graph based math exercises on http://mconsultingprep.com/chart-based-math-drills/ (not free). Graphs from cases are probably just as good.

Cheers

Guennael
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replied on Sep 14, 2018
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3 steps:

First, give the lay of the land, what the exhibit talks about

Second, read the data, what's the story

Third and most important, what's the insight, what will you do with this.

I had a case at BCG 1sr round, consisting of a half dozen exhibits, one after the other. I followed these steps, aced the case in 15 minutes, got into the 2nd round in spite of a disappointing 1st case.

There is a risk of over-complicating things in case studies. I'd second Guennael's pretty straightforward approach here and can verify that it's very effective. — Peter on Sep 17, 2018

Andrea
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replied on Feb 26, 2018
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As others suggested, I would suggest to leverage the framework you set at beginning and see to which elements of it the chart relates to and how. Once you have your mental/written list of insights next to your framwork buckets, I would circle the 3-4 key insights and say those first and then mention all others. This will show your ability to prioritize what is key vs. what is nice to have.

Hope it helps,

Andrea

Originally answered:

Chart reading resources

Anonymous G replied on Apr 24, 2018

MConsulting prep has a good chart quant resource to buy. It has follow up questions and is quite challenging!

Anonymous replied on Feb 26, 2018

Hey anonymous,

For me the best (and easiest) way to pull insights from tables or graphs is to try to relate with original framework/hypothesis, as well as trying to keep in mind what’s the overall goal of the case, so that when you’re reading them you can try to get insights that help solving the original problem

Best

Bruno

Anonymous F replied on Jul 22, 2016

Great answer, Dolf!! Thanks a lot!

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