# Is it possible to explain table calculations & LODs to your grandma?

**Siraj Samsudeen**Sep 12, 2016 3:22 AM

What was your reaction to the title? Did you laugh at the idea? Did you ask yourself "Explaining to my grandma, that too table calculations!"? Did you feel that it is a ludicrous idea and we should not waste our valuable time in preposterous pursuits like this? Or did you feel that it is a worthy goal to strive towards simplifying the presentation of these two complex areas?

Whatever your reaction was, let me ask you to visualize this - Can you please close your eyes and bring back in your mind the first time you encountered Tableau? How would you describe that experience? What words come to your mind? "Incredible! So simple! So easy! Intuitive!...." . Will you say that you were in "flow" with the tool quickly? Will you say that there was no friction between you and the tool and the tool disappeared into the background? Did you need to go through manuals or training videos to get into such a flow?

Now fast forward to the first time you had to do a calculation like YTD (year-to-date), YoY (year-over-year) Growth or just plain '% of Total' and you realized that you had to use table calculations in Tableau? How would you describe that experience? What words come to your mind? "I am lost", "So confusing", "These terms are so unintuitive - addressing, compute using, scope, direction, etc.". Have you watched the training videos on the topic? Have you checked out the manual and the knowledge base? Have you tried to read blog posts to get a better handle? After doing one or more of these things, did you feel comfortable that you have understood the concepts well? Or did you come back even more confused?

As part of my daily work, I have introduced Tableau to a lot of people and normally I see surprise and delight in their eyes. And when these users eventually start to use Tableau regularly and have to use table calculations, I often see confusion in their eyes and disappointment in their tone.

You might wonder - what is my intention here? Am I just complaining about table calculations and LODs without spending the time & effort to master them? Hasn't the community produced so many articles and videos about these 2 topics? Isn't Jonathan Drummey maintaining a list of links to follow for mastering table calculations? I agree - there are lot of such helpful articles. But most of them suffer from the Curse of Knowledge - You have to reach a certain level of expertise to understand them, but for most users who have not yet reached there, they don't know how to get there.

I was in this situation 3 years back. I have spent a lot of time reading a lot of blog posts and watching a lot of videos on table calculations. After quite a bit of effort, I had the feeling that I "got it". But that feeling was transitory - in a few days, I will encounter another problem which will perplex me. By reaching out to the community in the forums and reading through Jonathan Drummey's blog and many other posts in the community, I developed a list of thumb rules on where and how to apply table calculations. But I always had an uneasy feeling in my stomach about table calculations. I was always comparing in my mind how Powerpivot's approach to solving these problems seemed to make much more intuitive sense to me. So, I had this nagging feeling that even simple calculations like % of Total are complex in Tableau, whereas other tools have figured out a way to do it easily.

An unexpected event happened which gave me the first flash of insight about table calculations. I was staying in a hotel in Rheinfall (the town which houses the largest waterfall in Europe, near to Zurich in Swiss). The next day, I had to give a training to Unilever supply chain team on PowerPivot. After finishing up my preparation, I picked up a book on advanced excel as a way to relax and as a way to find more inspiration to connect with the Excel power users who would be my target audience. I was reading about some advanced options in regular Pivot tables in Excel. It is then I saw that menu which almost made me jump out of my bed!!! I fired up Tableau and went straight into the list of table calculations. I saw the striking similarity between the 2 menus - "Oh! This is what Tableau is trying to do in the name of table calculations. It is just another complicated term for such an intuitive thing.". That insight was the first in the series of insights I have received since then in the 2+ years since that fateful night.

In these 2+ years, I have continued to read more and experiment more with table calculations. I was also using Tableau to solve more and more complex problems. I have to admit - some of these problems were out of my reach that I had to reach out to Joe Mako for help. Each time I worked with him, I got some new insight, a new way to think about some aspect of table calculations.

In the meantime, I was also teaching a number of people how to master the table calculations. My aim was to give an intuitive framework that would help them to feel at ease. As I presented the framework each time, I felt satisfied about some aspects and unsatisfied about some aspects. I kept tinkering with it as I taught it to each new audience. Finally, 2 weeks back, I presented it to the local Tableau User Group (ChennaiTUG) to see whether I am able to explain my insights in a way that would benefit a larger audience.

The session ran for about 3-4 hours and here is the outline of the session:

- There are 3 paradoxical problems in the reporting world - Table calculations are a fitting and elegant solution to these pervasive problems.
- We mapped each of the 11 Quick table calculations to these 3 paradoxical problems.
- To understand partitioning, we took "Running Total" and put on our hat as a product designer to see what options would be needed to create a running total calculation if we are designing it from scratch. Then we mapped these options to the terms Tableau used like Partitioning.
- To understand Addressing, we took a "Diff from Previous period" calculation and we ran a simulation in the class. One person took a role as the post master whose job is to deliver mails to everyone across the table. The table was a like street with houses on both sides. We played a few scenarios to understand how the order in which the postman will visit the houses is dependent on the street layout and his plan (how he has arranged these letters). We then played a few scenarios to understand how the visiting order is impacted by the 2 options. Then, we mapped these scenarios back to our "Diff from previous period" table calculation to understand the role of "Addressing" in Tableau and how we can use different options to specify different visiting order for Mr.Tableau to collect the values to do his calculation.

Since it was such a serious topic, we have also had many diversions: We played 'find the 6 differences between 2 pictures' game and then tried to do something similar with the table calculations. We tried to connect the dots between Steve Jobs and table calculations. In the end, I had fun delivering the session. Judging by the feedback, I think the audience has enjoyed the fun approach to thinking about table calculations and also understood the topic well.

Now I want to make this available to everyone in the Tableau community. I have benefitted so much from the community especially from Joe Mako in one-on-one sessions with him and from Jonathan Drummey in reading and reflecting on many of his long insightful posts on table calculations. I also really liked the breath of fresh air that Shawn Wallwork has brought into the discussion on table calculations and LODs by his educational fun teaser - this was one of the ideas that inspired me to infuse some fun into teaching a complex topic.

My intention is somehow find a way to translate what I have presented in the live session into articles/videos so that many more people can benefit from it. But it is a time consuming task and I am only a beginner with respect to video editing and I have not produced any animation in my life - I need to invest significant time and energy to recreating the simulations in the form of videos. Before I invest my time and effort, I want to check with the community whether it would be useful. Do you think that table calculations and LODs are still hard to master or do you think that there is enough material out there that fulfills the need?

Here is my plan: In addition to creating videos to explain table calculations and LODs using an intuitive framework, I intend to create a list of 100 real-life business problems and then show how we can apply table calculations and LODs to solve them. I want to arrange these 100 problems in a curriculum-like fashion from simple to complex so that people at different levels can work on a path to master calculations in Tableau.

Now what do I need from you?

- If you are new to Tableau or still struggling to get a good handle on table calculations and LODs, then please be my audience. Please let me know what challenges you are facing in mastering these areas so that I can address them.
- If you have already mastered these 2 topics, then please be my mentor/guide. It is not that I understood every nuance in these 2 areas and there are definitely scores of people in the community who know these 2 topics much better than I do. I would definitely benefit from reviews of the materials I would create and also I would like to understand your insights into these topics as well.

If you are still wondering whether it is possible to explain table calculations to your grandma, the answer is yes - I do have a simple dialogue that can capture the essence of the table calculations in such a way that you can comfortably discuss table calculations with your grandma at the dinner table. But the decision rests with you - you have to tell me whether you think it would make sense for your grandma.

If you are wondering, who I am, here is my LinkedIn profile.