Have you heard the one about a pie chart?

It’s been almost four years since I attended my first Tableau conference in London and just over 4 years since I discovered Tableau.  I remember sitting in a few of the customer speaker sessions at the conference and I clearly remember one of the speakers joking about using Pie Charts. I smiled thinking I didn’t want to seem like I didn’t get the joke as everyone laughed along!  Then it happened again, another speaker and another pie chart joke!! Fast forward to today and now I’m the one doing presentations for various reasons and I can never resist sneaking in a really bad pie chart to highlight the need for good data visualisation.

So what is the deal with pie charts then? Why are they the ‘in joke’ of the data viz world?! If they are so bad why do they even exist and why is it one of the first types of charts you learn at school?

Most data visualisation books will talk about the use of pie charts and the reason why they get such a bad rep in the data viz world is because the human brain struggles to compare angles. Data visualisation is about making data more accessible and enabling understanding. If pie charts aren’t easy to interpret then they are simply not a good choice of data visualisation.

One of the dangers of pie charts is the use of colour, if you have more than a few slices in your pie then suddenly you have a multitude of colours that might not work together. I have seen so many where there are also similar colours being used and you don’t know which category is which.  I tend to discourage anyone from using pie charts at all especially if they are new to the data visualisation as it is easy to get it wrong. I usually tell people if it’s got more than 3 slices then don’t use pie charts, and if they are still keen to use them to maybe consider using a donut chart instead. The angles in a donut chart are easier to read and you can utilise the space in the centre for extra info, it’s still best to avoid too many slices though.

When I am training new analysts how to use Tableau or running a workshop on data literacy I do tend to talk a lot about pie charts, and I have loads of examples of really really bad pie charts. I personally think it helps to get people to understand what data visualisation is all about.  Rather than just joking about pie charts, I show them why they don’t always work and what other charts work much better.

I haven’t included a pie chart in any dashboard I have built since attending my first Tableau conference. I really struggle with choosing colours that work for my dashboards so I think it’s just better to stick with minimal colour selection and no pie charts!!

So let’s have a quick demo so I can briefly show you what I mean…

Let’s take some little league data using a pie chart to break down the number of runs by 5 different teams:

It is hard to see from the pie chart how much difference there is between the different home team’s runs, the slices all seem fairly similar. You can just about make out which team had the most runs, but you would struggle to see second place.

Now let’s use the same data but presented in a simple bar chart and one colour:

As you can see presenting this same data in a bar chart you can now quickly see that Bears are quite a bit ahead of the other teams, this wasn’t so obvious in the pie chart. If I then sort the bar chart into size order you now easily see which team is in second and third place. That isn’t possible with the pie chart, even if the pie chart had labels on it, it would still take some time to interpret.

I could give you loads of examples to labour my point, and show you alternative charts that work better than pie charts, but I will leave it there! There are lots of great data visualisation books and websites that will explain all this much better than I can. Go check them out!

Thanks for reading my latest blog.


Reflections of a Tableau User Group Leader

Why I love being a TUG leader!

I set myself some objectives for 2019 to give me a big nudge to keep developing myself. I even popped them up on my white board in my office at work to remind me of them and see if others would also make sure I had achieved them. It’s April already and I can honestly say that I am struggling to get going with most of them. Like everyone, life gets in the way, but one of them was about starting to blog so here goes!

Last week I helped to run the fourth UK Northwest Tableau User group (#NWTUG), afterwards I was absolutely buzzing after having such a good day and already thinking about the next one. With this in mind I came away thinking I need to blog about why I enjoy leading a user group so much. I am hoping this would inspire others to get involved in similar forums or even create them. So my first official blog will be about this…and I need to do it now before more time passes and I forget how that day felt!!

It had never really entered my head to create a user group, but when I was approached by Rory Heath from Tableau and Vicky Lockett from Interworks Europe about creating a Tableau user group in the Northwest I thought why not. This was almost two years ago and in December 2017 I ran the first Northwest Tableau user group.

I spent loads of time preparing for the first event; who might present, working out how long it would last, how I would get people to attend etc. I reached out to people I knew from the Tableau world to come along and present, and got loads of help and support from my first official Tableau buddy Simon Beaumont (and now Tableau Zen Master!). Simon had just starting running the UK healthcare user group so his experience with this kind of thing was invaluable.

I have to be honest on the morning of the first user group I was a bag of nerves, despite over 100 people registering to attend I was worried that no one would turn up. I think on the day we had over 90 people attend, all looking on me to make sure the day was a success and that they went away with their objectives met. So standing in front of 90+ tableau and data enthusiasts I had to get over my nerves and crack on. The day was a success with loads of great speakers, all the attendees seemed to be enjoying themselves and loads of people approached me afterwards about getting involved in future ones.

Leading on this kind of event on my own wasn’t easy and I quickly realised that I wasn’t going to be able to keep setting these up alone. Luckily Lorna Eden (a graduate of London’s data school) got in touch with me just before the first user group to say she had just moved back up north and was keen to get involved in the leading the Northwest group with me. Unfortunately she wasn’t around for the first event but I did pick her brains before the day to get ideas about what she thought should be included. Lorna was actually in Australia at the time, but whilst running a live poll using SLIDO to get to know the attendees she joined in from Oz!! I also got chatting to one of the presenters on the day (Colin Wojtowycz aka Datawoj), about whether he wanted to help run future user groups, we seemed to get on well so thought he would be great to get involved alongside me and Lorna.

Since the inaugural user group 18 months ago the three of us have now run three successful (we believe!) user groups, couple of evening events and then a full day event at Manchester Metropolitan University last week. It is so much more fun being part of a little team with Lorna and Colin, and I have really enjoyed getting to know them both. The three of us have very different ‘data jobs’ and I think this helps us to understand what different people may want from these types of gatherings. We have got together a few times between the users groups to talk about future user groups and also more recently we attended an event in Manchester where myself and Lorna presented about Tableau whilst others talked about PowerBI and QLIK. It was nice to attend this without having to do the organising, and despite hearing how good the other products are, Tableau is still the best in our eyes…!

I also help to run the UK Healthcare User Group too now! When Simon Beaumont asked if I would help him run the UK Healthcare TUG too, I couldn’t resist. I had attended a few of the users groups and always really enjoyed going to them. The fact that it also in healthcare I felt that this would be great to help meet other fellow healthcare analysts and leaders, and share ideas that would specifically support my work as NHS leader.

Ok so I have talked about my user group journey but why do I like doing these so much?!

It may be hard to believe if you have seen me present or if you have worked with me, but I can be shy and my shyness in my youth was crippling. I have always however tried to push myself out of this innate shyness and challenge myself. When I was 18 I travelled alone to Australia for my gap year and then had to force myself talk to people I didn’t know, but if I am being really honest with myself and think back (way back!) about that time I generally waited for people to make the first move and start chatting to me first.  I have always recognised how beneficial networking for work is but again struggled in large groups to talk to new people and always struggled to find forums to reach out to.

Over the last couple of years I have done a lot of presentations external to work which has really helped to grow my confidence in public speaking. My discovery and experience through using and implementing Tableau have given me something I am now really passionate to speak about to whoever will listen. The more you present the easier it is, but don’t get me wrong I still get nervous. One of the great things about user groups is the opportunity to network with new and different people, sharing ideas and experiences is a great way to develop yourself and your work. I watched the attendees on Monday to see how many people reached out to speak to new people, but noted that generally people end up talking to people they know. This is exactly what my preference is too and we are after all ‘data’ people, and being one of the organisers means that more people approach me to talk. I however tried my best to talk to new people because I know like myself that not everyone is comfortable to do so. On reflection, I will definitely talk to Lorna and Colin about how we can get people talking to each other more. We have done similar things at work so I do have ideas, but I won’t share them just yet. Don’t want to scare future attendees off ha ha.

As I have said presenting about things I am passionate about gives me the confidence to talk, and presenting in these safe environments is a great way to get that experience.

We had about 70 people attending our Northwest group last week, with a few other Tableau user groups leaders also attending from other parts of the country (London/Yorkshire/Midlands) which was great. Another opportunity to share ideas for future events with fellow leaders! We actually had nearly 100 people registered for the event, I was impressed with the turnout despite the attendance rate but actually felt sorry for those who didn’t end up attending as they totally missed out on so much learning and networking opportunities. Hopefully we will see them at the next event!

As I said I came away from Monday loving the user group, the attendees seemed to get loads out of the day. We followed the day with a trip to a local pub and a lot more people joined us than I would have imagined, which again I think is a good sign of a successful day more than the lure of free drinks?! Well maybe…

One of my favourite things about running a user group is bringing people together. It is also great to create a fun environment for these kinds of events, I love a game! Work doesn’t always have to be dull, you can’t underestimate how much better people work if you motivate them in the right way. Happy workers and all that! We had loads of the attendees last week come over and say how much they enjoyed the day, if this isn’t reason enough to set up the next one then what is?!

My 5 top reasons for attending a user group:

  • Ideas gathering to take back and explore
  • Learning new tricks
  • Meeting new people
  • Break away from your usual day to enable reflection…
  • They’re fun!

My 5 top reasons for leading a user group:

  • All of the above plus…
  • Working with new people
  • Helping others by sharing experiences and ideas
  • Bringing people together
  • Ability to motivate people to learn

I am sure there are rules over the length of blogs…but it is my first after all, so I will learn and improve I am sure. I have really enjoyed writing this, it is really good to look back and reflect!

Hope you have enjoyed reading my first blog. Feedback welcome!