Welcome to my guide on mastering the 3-Level Drill Down in Tableau!

In this tutorial, I show you step-by-step how to make the most of using dynamic zone visibility to create this functionality. We'll go through both scatter plot drill downs from Region → State → Postal code and then replicate that as a bar chart. 

You can easily make this a map drill down by changing the chart type. That's it!

🔍 What you'll learn in this video: 

1. The basics of drill down functionality in Tableau
2. Hands-on demonstrations, tips, and best practices
3. How to interact with the data

💡 Why is this important?

Drill down capabilities allow analysts to explore data from a broad overview down to granular details. By mastering the 3-level drill down, you can uncover hidden patterns, insights, and trends that might be overlooked in higher-level analyses. 

📌 Prerequisites: 

A basic understanding of Tableau's interface and primary functions will be helpful, but beginners will be able to follow along as well!

If you are following along, be sure to pause the video along the way as you repeat the steps.

Day 3 of the Visual BI workshop was the day I was looking forward to the most.  I was very interested in hearing Stephen’s approach for analyzing data, which he covers in his book Now you see it.  There was one common theme throughout: keep things simple and clear, but don’t dumb it down.

Here are my key takeaways/notes:

• The word “see” in the title represents the analytical thought process: Search => Examine => Explain (SEE)
• Things to look for in a skilled data analyst: interested in the data, curious, self-motivated, imaginative, open minded and flexible, skeptical, honest, has a sense of what’s worthwhile, attentive, methodical, analytical, synthetical, has an eye for patterns, knowledge of the data, knowledge of effective data analysis practices
• The context we perceive is influenced by the surroundings.
• Exceptions can be a result of:
1. Erroneous data
2. Extraordinary events
3. Extraordinary entities
4. Randomness
• Highlight exceptions that are out of the range of “normal” or “standard”
• Always ask “Compared to what?”
• The tools we use need to make common interactions easy.  The tools should allow the train of thought to continue.
• Cycle plots are useful for cyclical and linear patterns.
• Linear trend lines on time series can be misleading; use with caution!  Consider moving averages as an alternative.
• Log scales are useful for measuring rates of change.  Lines with similar slopes will have similar rates of change.
• When looking for leading and lagging indicators, it can be useful to shift the time of one of the indicators.
• Bump charts are a good way to see how rankings change across different dimensions or measures.  Learn how to build one in Tableau here.
• The mean represents the quantitative center and is highly influenced by outliers.  If you want to look at dispersion around the mean, use standard deviation.
• The median represents the ordinal center and is better than the mean for showing the “typical” value.  If you want to look at dispersion around the median, use percentiles.
• It’s a good to idea to start an analysis by looking at a distribution of all values.  This will help you quickly identify outliers and the overall shape of the data.
• You shouldn’t remove outliers from an analysis until you understand why they are outliers.
• This is a really cool analysis of pay ranges by level and gender.  You could easily include a strip plot on this.
  
  

That’s it!  Three days of learning that I’ll never forget.  These courses were easily worth the money.  You’ll be able to apply so much immediately upon returning to your regular job.

Day two of Stephen Few’s three-day Visual Business Intelligence Workshop centered around his book Information Dashboard Design.  This class included quite a bit of critiquing of dashboards from “BI” vendors, a look at some of the better work, and a bit of hands on creating our own designs.

Like day one, these are the key points I wrote down (nowhere near the entire content of the course) that we should all reinforce in our work.

• Well designed dashboards and well designed software allow for rapid visual monitoring, which has a three-phase analytical approach:
1. Scan the big picture
2. Zoom in on important details
3. Links to supporting detail
• The visual display of a dashboard needs to match the reader’s mental model.  If the reader does not have a mental model, then you should sit with them to develop one.  Avoid asking them “What do you want your dashboard to look like?”, rather get a sense for what questions the reader expects to be able to answer.
• Be aware of the 13 common mistakes in dashboard design
• A great way to convince people of how simple data visualize can be is through Stephen’s “Graph Design IQ Test”.  Answering the questions wrong is pretty funny.
• There are four characteristics of a good dashboard design:
1. Exceptional organization
2. Data is condensed in summaries
3. Data is specific to and customized for the task at hand
4. Concise, clear and often contain small display mechanisms
• Never ask people what they want their dashboard to look like.
• Common dashboard data consists of:
1. Measures of what’s currently going on
2. Each compared to something to provide context
3. Each evaluated to declare its qualitative state
• Don’t design a dashboard only to highlight problems and exceptions.  The dashboard should be meaningful even when all is well.
• Objectives of visual design:
1. Eliminate clutter and distraction
2. Group data into logical sections
3. Highlight what’s most important (Place what’s always important on the upper-left)
4. Support meaningful comparisons / give your data context (this was a them that came up over and over again)
5. Design for aesthetic appeal (but don’t add fluff to add fluff)
• Use soft, natural colors
• Soften the background of the dashboard (Stephen likes to use a soft yellow)
• Charts and text should be crisp and clear
• Use good fonts (stick to Sans Serif on dashboards)
• Only include one font style per screen
6. Navigating to additional important needs to be easy and should support our train of thought.
1. Scan the big picture
2. Zoom in on important specifics
3. Link to supporting details

Stephen Few is running his three-day Visual Business Intelligence Workshop this week in Austin, TX.  He and I had been emailing back and forth and he thought maybe this wouldn’t be a worthwhile course for me, but I told him that I strongly believe that seeing someone teach in person is way better than reading books and sitting on webinars.  You simply can’t get the same level of interaction and communication without attending or conducting training live, in person.  I see this every time that I run training classes; those classes that are in person are way better.

Day one of the course, based on Stephen’s book Show Me the Numbers, has exceeded my expectations.  I’ve read all of Stephen’s books, so yes, much of the material was repeat, but the discussions in the class and hearing Stephen explain, in detail, his beliefs, extended the content way beyond what the book could possibly cover. 

Here are some of the key reinforcements and takeaways I noted from Tuesday’s class.  Many of these are “duh, of course” type of notes, yet good to always be reinforced.  This is a brain dump, so don’t expect any semblance of fluidity in my notes.

• You should strive to include context and comparisons in every table of chart you create.
• Line charts do NOT have to start at zero because you’re looking at patterns, unlike bars, which must start at zero because you’re comparing lengths. 

This was a big question I had before the course.  I typically always create line charts that include zero, but now I understand better why that’s not always necessary.  In the end, the patterns of the lines are easier to see when you do not start at zero.  Be careful though, you may have to alert your audience that the axis does not start at zero if they’re unfamiliar with the data.

• There are eight types of relationship graphs:
1. Time series
2. Ranking
3. Part-to-whole or contribution
4. Deviation
5. Distribution
6. Correlation
7. Geospatial (note this is different than geographical)
8. Nominal comparison
• “Don’t bury the truth under a layer of beauty or abstraction.”
• There are four primary methods for encoding values:
1. Points
2. Lines
3. Bars
4. Boxes (which represent ranges of low values to high values)
• ColorBrewer.org is a great resource for understanding color choices.
• Adding data points to line charts is good for making comparisons between lines, but keep them light & small.  Don’t use separate shapes if you’ve colored the lines.
• Bubble size is appropriate to use for data points if precise comparisons are not required.
• Avoid dual-encoding.  I’m glad I asked about this, because it’s a practice I employ, but no longer will. 

As an example, if you’re looking at a map that has a circle for each state that is sized by sales, you should not also color the circle by sales.  If you want to use color, it should be another element that adds to the interpretation (like profit ratio).

• This one shocked me – It’s ok to use pie charts on maps (assuming there aren’t but two or three slices) because there’s no better way to subdivide bubbles on a map.  In other words, pie charts are your only choice in this case.
• Three good examples of representing a single distribution are histograms, frequency polygons and strip plots.  I’ve never used the latter two, so I’m going to be looking into those more.
• Colors:
1. Use only soft, natural colors.  Tableau’s medium palette works well.
2. Use fully saturated colors for emphasis, otherwise they become visually exhausting.

Of course there was way more content than this; these were merely the key points that I wanted to ensure I reinforced to myself.  Look for summaries of the next two course as the week progresses.

From Sports Chart of the Day:

ESPN aired the 50,000th episode of SportsCenter last night, an incredible accomplishment for the self-proclaimed Worldwide Leader. That works out to roughly 1,500 episodes a year for the the 33 years of ESPN's existence. But as we can see below, those 50,000 episodes have not been distributed evenly.

Followed by this chart:

I’ll give you a couple of minutes to figure out what’s wrong…

Give up? 

Cork Gaines is using a line to connect uneven intervals.  While it looks like a steady increase, was it really?  Were there the same number of episodes every month between Sept 1979 and December 1998?  I highly doubt it.

I recreated the data in Excel, and low and behold, when I build a line chart with these six data points, it looks identical to Cork’s.

Clearly Cork used Excel to create the chart.  And clearly he didn’t know that he should not use a line to connect unequal intervals of time.

There are a few basic guidelines for line charts (Stephen Few):

1. Lines should only be used to connect values along an interval scale (with a couple of exceptions).
2. Intervals should be equal in size.
3. Lines should only directly connect values in adjacent intervals.

Cork’s chart breaks all three guidelines.

The best way to represent time-series data with unequal intervals of time is with a bar chart.

I was teaching a data viz class at work yesterday and I tried an exercise that I’ve never done before.  The idea came from this blog post by Santiago Ortiz on visual.ly.

To set that stage, we covered attentive vs. preattentive processing, three forms of preattentive processing (I skipped motion), and the Gestalt principles of visual perception.  Nothing ground breaking there, but a necessary base/toolkit that everyone should have.

After the initial training, I had them grab some markers, head to the white board, and think of as many possible ways to visualize two simple numbers: 75 and 37. 

At the end, we picked the best visualization.

Here’s a sample of what they came up with (there was plenty more to the left and right):

Like the author of the blog post, I had no idea how this would go.  It could have been a total flop, but it was the exact opposite.  We spent a good hour discussing two simple numbers!  And it was incredibly rich discussion.  We went through each and every sample, discussed the pros and cons, and compared them all to determine which one we like best.

What I found very interesting was that everyone made an assumption that the base was 100, but the directions never said that.  All I gave them was two numbers.  This led to an awesome discussion about needing context when presenting data.

Give it a shot!  Grab a few fellow data viz nerds and do this at lunch.  Or better yet, over dinner and beers.

Charles Schaefer’s session at TCC11 “Understanding and Working with Chart Types” included this decent flow diagram for choosing a chart type.  As the title says, it’s “A Thought-Starter”.  In other words, use it as a way to get you going down the right path.  This absolutely shouldn’t be taken as gospel; use your common sense.  For example:

1. Don’t ever create 3D area charts.  In fact, don’t ever create a 3D chart of ANY kind.
2. Never create a circular area chart
3. When created a stacked column chart don’t connecting the same colored bars with lines.

You can download the materials from Charles’ session here.  Included are a JPG and PDF version of the flow chart.

The flowchart originates from a blog post back in 2006 on The Extreme Presentation Method blog.  This blog, in turn, links to an interactive version of the chart chooser on Juice Analytics.  Although Tableau does a lot of this thinking for you, definitely check out the interactive tool to get a feel for some best practices and download the sample excel workbooks to quickly recreate these charts yourself.

The latest Dashboard Insight contains a whitepaper written by Tableau that walks you through a five-step process for creating effective dashboards.  Basically, it’s a recipe card.  I’d encourage you to read it below or here.

The whitepaper below is pretty much identical to a whitepaper Tableau wrote in 2008, except it looks cleaner and shows some of the features added in Tableau 6.