Data chart labels: inside or outside?

This post on the F1 Instagram account has an interesting solution to the labels of a data chart:

• When the column is tall enough, the label is put inside with a contrasting white font color

• If not, the label is put on top, if possible with a font color that matches the column

The advantage is that this enables you to make the column graph taller as a whole (no need to budget extra space for the labels), and it is easer to put a background image as most labels (in tall columns) have enough contrast against them.

The vertical orientation of the labels though…

Combining column and line charts

Below is an interesting chart from McKinsey. It combines a column chart with a line chart. The chart only works when a column has a reasonable size though.

I am not aware of any presentation software that can produce these (including SlideMagic), so this might have been bespoke illustration work.

Link of the original post.

Dashboards and reports

For periodical update meetings, you often can use the same presentation with just the numbers updated. When the audience is internal to the company, many will just use a spreadsheet printout rather than transferring the data to a presentation.

The result, a presentation that looks like, well, a spreadsheet.

• There is more information presented than needed for the meeting

• Numbers are highly precise and not rounded up

• Fonts are tiny, as the spreadsheet tries to show everything on 1 page’s width

• Colors and fonts are those of Excel, not the company

• The last 2 rows of the table moved over to the next page

• Etc.

If you need this report often, it is worth investing some time in setting up your spreadsheet properly.

• Leave your “engine” untouched and create an entirely new work book that is your “presentation”

• Get rid of spreadsheet gridlines and show the page cut offs so you get a clear view of the boundaries of your “slides”

• Set colors and fonts the same way you would do in PowerPoint

• Now build your slides page by page, by pulling in the data from the engine sheet, round numbers up as you go ( / 1000, show 1 decimal, etc.)

• With these types of reports, you variability between slides will be in the column widths, not so much in the rows. To keep your “deck” all in one workbook, move horizontally, and add pages to the right rather than below

(Optional) The next level up is to introduce shapes and other graphics in your spreadsheet, and you can get to the same level of finish that you can achieve with regular presentation software.

Diversity

This is an interesting graphical representation of the US workforce:

Source: https://www.visualcapitalist.com/american-workforce-100-people/ on Visual Capitalist.

It is very cute, but does not do a good job at communicating the actual data (percentage breakdown by sector). Also, since this graph tries to make the point of diversity, the characters in the illustration do not represent the gender and race balance of the work force.

One idea to tackle this. Add multiple dimensions of data: sector, gender, etc. to the characters, and then render multiple iterations of the 100 people, each time grouped differently to focus on a specific statistic. The opening slide is a random permutation of the entire group.

Useful graphics illustrations

I am usually not a big fan of illustrations that visualize data. Below is an example (with data from February 2022). The soldiers might as well have been represented by straight bar charts.

This article in the NYT though, was pretty effective. Representing unused office space with repetitions of well-known landmarks. People can instantly relate to, understand, and internalize the amount of space we are talking about.

(BTW, these illustrations are made by Kaylie Fairclough)

Women in the workface

On women’s day, here is an interesting visualization by The Economist to show the role and influence of women in the workforce:

What is used:

• Big, bold, fat lines

• Color coding using a gradient based on the last available year’s ranking

• (Not visible on the static image) When you hoover over a line, it lights up with the rest being faded out

Lines that break the pattern will pop out (Israel, Hungary).

One caveat though, these are all 29 reasonably wealthy countries. The situation might be a lot worse in the other 150+ countries that are not on this list.

The little details

I was busy doing a chart makeover of the following chart:

global co2 emissions, broken down by income
no surprises here

ht @_hannahritchie pic.twitter.com/2OqPMmUUUp

— ian bremmer (@ianbremmer) January 20, 2023

To get to this result:

To found out that the columns don’t add up. In case of the left column, it is probably a small rounding error, but on the right, something got lost in translation.

About errors:

• Don’t blame the spreadsheet, you are presenting a chart, not your backup model. If there is a rounding issue, fix it manually (I usually adjust the biggest category, so 43.1 would become 43.0 in this case). I always argue to disconnect your chart from the spreadsheet for your final document.

• Even tiny mistakes can make people doubt all the numbers in your entire deck. Number charts should be simple, and it is a 5 minute investment to quickly check them on a calculator. Worth the investment!

In this case, the hidden calculation error shows the flaw in the type of chart chosen. The stacked column is more intuitive and shows how things are related. For the horizontal bar, I had to think for a second to understand what it means, and I did not instantly spot the error.

Agario-style

This amazing visualization shows the history of Europe and the coming and going of various empires in the style of the Agario video game, where bubbles collide and merge.

This video was made using Adobe After Effects. In theory you could do something like this in PowerPoint: a slide for every year with animations and then loop the whole thing. It is a lot of work though.

Failing the 10 second test

It is tricky to understand this stacked column chart I found here on Twitter, given the negative, below the horizontal axis boxes.

After a bit of studying, I get it (I think). Categories below the axis show a decline. But what does the height of the column above 0 represent, and the height of the total column (the sum of the absolute values of all the boxes).

Eventually, you will figure it out, but “eventually” takes too much time to put in a live presentation.

Bar chart formatting

This chart can be improved in many ways (source), you can see it without understanding German…

• No need to repeat “Mrd. Euro” (billions of Euros) at every data point, just put the unit at the top

• The data labels of the second data series is missing, as is the total

• The color of the 2nd data series is too light (probably to make the text readable)

• I would right-align the row labels

Follow the chart

For the analysts who are in the trenches crunching the numbers behind slides (often after 18:00).

Presentations of financial data often evolve. You start with a relatively naive model, create some slides and iterate the numbers. Slowly, your team starts understanding what actually matters and discovers with drivers to focus on.

Instead of the exact numbers in your spreadsheet, your manager asks you to group this, that, and that into one number, quickly offline. Then another scenario, put that number in, quickly off line. Then another one.

In each round, you re-run your model, take out a calculator, scribble the summarized numbers, and update your slides. This takes a lot of time and is prone to errors.

Instead, build a quick layer on top of your ‘old’ model that spits out the required numbers quickly. In fact, make it a habit that every number in your presentation is pulled directly out of a cell in a spreadsheet.

My financial models would usually have these layers:

1. Data dump: straight copy-paste of raw input data, or data entered straight from a financial report without thinking, make sure the total is correct at the bottom. You get a new set of data: simply overwrite the entire worksheet, or add a column.

2. Model engine, this one does the hard lifting and runs your analysis

3. Bridge: this worksheet pulls numbers out of the engine and produces the required numbers for the charts (relevant to the scenario I described above)

4. (Optional) Slides. A small box that matches exactly every page in your presentation, with the exact numbers that appear in each slide. Useful if you need to run periodical updates of your presentation (weekly, monthly, quarterly results for example).

De-cluttering axes

In scientific documents, there are chart making conventions that make sense, clearly labelled axes, titles, etc. etc. Use these charts in your article that you submit for publication in a prestigious paper. For an on-screen slide show however, you could deviate from this standard. Your objective is to communicate the findings as best as possible, referring to the paper for the details.

See the example below (source), lots of duplication in axis labels.

You can make the page a lot calmer be omitting some of these labels. I quickly cut and paste the elements in the image below. (This is not a makeover, just a super rough reshuffle to show you what I meant).

Statistics: vaccine effectiveness might seem higher than it is

I love digging into COVID-related statistics. Recently, this paper was published that shows how vaccine effectiveness in local communities can be a lot lower than at the national level. Seems counter intuitive, but this chart explains the math.

I have added this slide to the SlideMagic library, so you could use it in your own presentations as well.

Public corona data dashboards

BI (“Business Intelligence”) dashboards with data used to be a corporate thing. Firms such as my previous employer McKinsey would advice clients what metrics to put on them, and how to display them. This is tricky, there is an infinite amount of data to choose from, and even more options to slide and dice the figures.

The COVID outbreak has created many country-wide public dashboard with data. In Israel where I am based, a large tribe of “amateur” statisticians has emerged that runs and discusses analyses on Twitter. The other dashboard I had a look at is the Dutch one (part of my family still lives there).

• Dutch board

• Israeli board (use the translate option that is offered by the Google Chrome browser)

The approaches are different, and I prefer the Israeli one.

• The Dutch board looks very pretty, has lots of explanations in text, and has useful maps of regions with color coding. The problem is that it stretches out over many, many, pages, and priotises static data over time series.

• The Israeli one is just one page, with lots of time series graphs, so you can see things develop over time. And not for basic statistics such as overall cases, benchmarks can get very specific. Benchmarks are normalised so you compare apples with apples (i.e., cases / 100,000 by vaccination status). Also, government policy and benchmarks are tightly integrated. The government wants to encourage parents to vaccinate children, so there are statistics specifically aimed at that target segment. Another example: after discussions whether to close the airport or not, stats about airport tests were published (split by country, so citizens can make the call to travel somewhere or not based on their personal risk appetite).

The biggest advantage of the all-on-one-page approach is that people start to understand it, and come back to it very often to get the latest data, even venting anger when it is not updated on a day.

Data visualisation to involve the public in decision making and/or influence day to day behavior.

——-

PS. Israel does a PCR test for every single arrival at its airport, so the arrival statistics on the Israeli dashboard are probably one of the best global indicators of what is going on in a particular country.

To stack or not to stack?

Two charts about a new sub-Omikron (BA.2) variant in Denmark. This line graph shows 3 variants as a % of all sequenced samples in Denmark.

Source: https://twitter.com/DrEricDing/status/1485456877723045891

The chart below shows the total number of variants found in the samples. The stack approach does a much better job to give the full picture of what is actually going on,.

Source: https://www.covid19genomics.dk/statistics

With just one data series, showing a share of the total as a stack or line (column) is the same chart. As soon as you have more than one, pick a stack chart so the audience can see the data in context.

Bar versus column chart

The chart below could have been made a lot better using a bar chart. You can avoid the many legend labels, which have a 1-to-1 relationship to the columns

Image source

Even better than I did

This Venn diagram is a great visualization of why you still see vaccinated people in the hospital.

I gave it a go myself a while ago, but this visualization is better. Source of chart: RIVM, source of image. One improvement suggestion: switch the colors red and green.

The case for not rounding numbers

In 99% of slides, it is better to round financial data. $1.9m is easier to read than $1,898,456.34. Also the rounded number is more in line with a financial model that relies on rough assumptions. If you project your company sales in 10 year down to the dollar, you lose some credibility with your audience.

In some situations, the opposite approach can work. Look at this poster below of an Israeli anti-vax group who makes the argument that the money that is spent on encouraging hesitating Israelis to get a vaccine, could have been used better in a different way. (I leave pro and anti-vax debates out this blog, although you might guess in which camp I sit).

Here the big number actually works. Anyone looking at this big amount of money instantly starts comparing it to other lump sums you know: how much do you make as an individual in a year, how much does a car cost, how much does an apartment cost. Also, the precision and suggested accuracy of the number adds to the drama. This is a similar effect that National Debt Clocks try to convey.

The correct way to look at these numbers is to relate them somehow: $ per citizen, % of total corona-related cost, compared to other government advertising campaigns, etc. etc. After that, you might still conclude that it is high, but you used the correct metric.

Don't make them study the graph

A random chart on Twitter made me pause to see what is actually graphed. The chart title suggested a positive correlation, but the line is actually sloping down.

On closer inspection you see that the vertical axis is “low is good, high is bad”, and the horizontal axis is “left is bad, right is good”, also the horizontal axis talks about “decline” instead of “growth”, so a positive number is actually a decline.

To analyze data, it is OK to ponder and study a chart. In a presentation of final results, not.

McKinsey slide makeover

A saw a slide by my former employer coming by:

It has a very sophisticated image effect: look how the background of the bars in the chart are part of one image. Still, there is room for improvement. I quickly replicated the chart in SlideMagic with a few changes.

• I brought back the more traditional, very in-your-face alternate coloring of the bars, blue for 2021, grey for 2020 and a legend, instead of the repetitive text labels with the years.

• I increased the size of the industry sector labels

• By replacing 910b and 582b by 0.9 and 0.6, I could get rid of the “t” and “b” in the bar label.

But the analysis of the slide can be pushed further. The main point of the slide is how markets have bounced back over the past year, which is independent of the ranking of the market capitalizations of the sectors. As an alternative, I constructed the combined table/bar chart below, de-emphasizing the absolute value of the market capitalizations, and using the bar chart to highlight the % increase in market valuation. The inside here is that all sectors grew more or less the same over the last year (except fashion, probably reflecting less dressing up for work.

I have added the slide to the SlideMagic slide library, look for “COVID” and they will show up. Emails subscribers: if the slide images don’t show up in the email, please open the link to the full blog post.