Marimekko wGT

What I did on my summer vacation (hint: it’s about Tableau v10 and Marimekko charts)

This summer while beta testing Tableau v10 I was very curious about the new mark sizing feature. Bora Beran did a new feature video during the beta showing a Marimekko chart aka mosaic plot. There have been a few posts on building Marimekko charts in the past by Joe Mako, Rob Austin, and a not-quite-a-Marimekko in an old Tableau KB article, but the two charts required extra data prep and the KB article wasn’t really a Marimekko, so I was really interested in what Tableau v10 could do.

I asked Bora for the workbook and he graciously sent it to me. (Thanks, Bora!) I found a problematic calculation, in particular a use of the undocumented At the Level feature that could return nonsensical results if the data was sparse. I rewrote the calculation, sent it back to Bora, and he came back asking if I’d like to write a blog post on the subject. (Thanks, Bora.) There are two lessons I learned from this: 1) the Tableau devs are happy to help users learn more about the new features, and 2) if a user helps them back they will ask for more. Caveat emptor!

Over the course of the next few weeks I did a lot of research, created a workbook with several dashboards & dozens of worksheets, arranged for Anya A’Hearn to sprinkle some of her brilliant design glitter and learned some new tricks, and wrote (and rewrote) 30+ pages (!) of documentation including screenshots. Martha Kang at Tableau made some edits and split it into 3 parts plus a bonus troubleshooting document and they’ve been posted this week, here are the links:

On Gender and Color

As part of the design process Anya and I had some conversations about how to color the marks.  The data set I used for the Marimekko tutorial is the UC Berkeley 1973 graduate admissions data that was used to counter claims of gender bias in admissions so gender is a key dimension in the data and I didn’t want to use the common blue/pink scheme for male/female. It’s a recent historical development and as a father I want my daughter to have a full range of opportunities in life including access to more than just the pale red end of the color spectrum in her clothes, tools, and toys. Anya and I shared some ideas back and forth and eventually Anya landed on using a color scheme from a Marimekko print she found online.

Screen Shot 2016-08-24 at 10.58.30 PM

Anya is going into more detail on the process in her Women in Data SF talk on Designing Effective Visualizations on Saturday 27 August from 10am-12:30pm Pacific, here’s the live presentation info and the virtual session info. It’s going to be a blast so check it out!

So that’s how I spent my summer vacation. Can’t wait for next year!

 

Screen Shot 2016-08-17 at 12.12.24 AM

When 576 = 567 = 528 = 456: Counting Marks

Tableau’s data densification is like…nothing else I’ve ever used. It’s a feature that is totally brilliant when it “just works” like automatically building out a running sum on sparse data and mind-taxingly complicated when a data blend’s results go haywire because densification was accidentally triggered.

What I’ve historically taught users is to always ALWAYS look at the marks count in the status bar as a first way to detect when data densification occurs. Here’s Superstore Sales data with MONTH(Order Date) on Columns, Region and State on Rows, there are 499 marks and we can see that the data is sparse by the class that are missing Abcs:

Screen Shot 2016-08-16 at 11.52.15 PM

If I add SUM(Sales) to the Level of Detail Shelf and set it to a Running Total Quick Table Calculation with the default Compute Using of Table (Across) so it’s addressing on Order Date then I see 576 marks and all the Abcs are filled in, this is Tableau’s data densification at work:

Screen Shot 2016-08-16 at 11.55.19 PM

However, here are three additional views all still using the same pill layout and Quick Table Calculations  showing three different marks counts (567, 528, and 456):

Screen Shot 2016-08-16 at 11.59.11 PMScreen Shot 2016-08-17 at 12.00.55 AM

The marks count is changing based on a variety of factors, the different quick table calculations used (running total, difference, and percent difference) are a part of it but the underlying behavior depends on whether a mark is densified or not, the pill arrangement, and whether or not a densified mark has been assigned a value (including Null) or not. Prior to Tableau version 9.0 these all would have been counted in the marks count and the views would show 576 marks for each, Tableau v9.0 changed the behavior to only count the “visible” marks.

I’ll walk through the above there examples. In this one the Running Total has been moved from the Level of Detail to the Rows Shelf and there are 567 marks.

Screen Shot 2016-08-16 at 11.59.11 PM

The reason why is that even though those combinations of Region, State, and Month have been densified for states like Iowa that don’t have any sales in the first month(s) of the year (more on how I know that below) those densified marks don’t have any assigned value (even Null) so they are not counted in the marks count nor are they counted in the Special Values indicator in the lower right.

In this view using the Difference calculation there are 528 marks and the Special Values indicator shows 48 nulls (528+48 = 576). In this case the Difference calculation is using the LOOKUP() function that is returning Null for the densified values.

Screen Shot 2016-08-16 at 11.59.11 PM

Finally in this view using the % Difference calculation there are 456 marks and the Special Values indicator shows 120 nulls (456+120 = 576). In this case the % difference calculation is spitting out extra nulls due to divide by 0 results.

Screen Shot 2016-08-16 at 11.59.11 PM

The difference is due to a change made in Tableau v9.0 where the marks count now only counts “visible” marks (Tableau’s term), where the definition of a “visible” mark is complicated, they are the “Yes” answers in the table below:

Screen Shot 2016-08-17 at 12.09.17 AM

Now one of the ways I’ve been used to checking for densification is selecting all the marks (either by Right+Clicking and choosing Select All or pressing Ctrl/Cmd+A) and then hovering over a mark and Right+Clicking and choosing View Data… or waiting for the tooltip to come up and using View Data. For example here’s the select all View Data in v9.0 for the % Difference on Rows view, the yellow cells indicate where data was densified and there are 576 rows:

Screen Shot 2016-08-17 at 12.12.24 AM

However, that doesn’t work anymore in Tableau v10.0, there was change made to the Select All functionality such that Select All only gets the “visible” marks, here’s that same view data in v10 and there are only 456 rows:

Screen Shot 2016-08-17 at 12.12.58 AM

So Select All doesn’t work the way it used to, and the marks count can change in “interesting ways” (and we haven’t gone into what things like formatting Special Values can do), so what can we do to spot densification? There are three workarounds for this, all documented in the right-most column of the table above:

  1. Select a discrete header or a range of headers, wait for the tooltip to come up, and click on the View Data icon.
  2. Right-click in the view (but not on a mark) and choose View Data…
  3. Use the Analyis->View Data… menu option.

All of these will show the densified values, here’s an animated GIF of selecting Iowa selected in the Difference on Rows view where we can see the  two Null values:

2016-08-17 00_21_03

However only one of those is actually densified, to tell that exactly we need to add a field that actually has data. In this case I’ve added SUM(Sales) to the Level of Detail Shelf and the View Data for Iowa now shows that it’s really only January that is densified, since there’s nothing at all in the January SUM(Sales) cell:

Screen Shot 2016-08-17 at 12.27.28 AM

Conclusion

The marks count is not a reliable indicator of the volume of densification and we need to resort to various selection mechanisms and the View Data dialog to more specifically identify how much has been densified. I’m not a fan of these changes: what I’d really like Tableau to do is to add a count of densified values to the status bar and details on what was densified to the default caption and the Worksheet->Describe Sheet… Until that time, though, hopefully this post will help you keep track of what Tableau is doing!

Here’s a link to the marks count workbook in v8.3 format (so you can open it up for yourself and see the differences in different versions).

Screen Shot 2016-07-13 at 2.29.44 PM

Getting the Version of a Tableau Workbook in a Few Clicks

In helping other Tableau users as part of DataBlick or my pro-bono contributions to the community I get a lot of Tableau workbooks in a lot of versions, in the last two weeks I’ve received v8.3, v9.0, v9.2, v9.3, and v10beta workbooks and when I edit them I need to make sure I’m using the same version of Tableau. And I’m often frustrated because I’ll open the workbook in the wrong version of Tableau and get this message:

Screen Shot 2016-07-13 at 2.30.52 PM

or this one:

Screen Shot 2016-07-13 at 2.31.34 PM

And then I have to open it up in other versions which can take awhile. I shared this problem in a Tableau Zen Master email thread and Shawn Wallwork replied with his trick for Windows that only takes a few seconds, and I was able to take that and come up with one for the Mac as well.

The basis for this technique is that the version of the Tableau workbook is stored in the XML of the .twb (Tableau Workbook) file, in particular the version attribute of the <workbook> tag, and we can open up the XML in any old text editor, I’ve highlighted the <workbook> tag that shows this workbook was created in version 9.1:

Screen Shot 2016-07-13 at 2.29.44 PM

However a .twbx (Tableau Packaged Workbook) is stored as a zip file so I’ve always just opened workbooks up in different versions of Tableau until I found the right one or once in awhile took the time to fire up a zip application, extract the TWBX to a folder and then looked at the .twb file. Both of these methods are slow. Shawn pointed out a shortcut on Windows using the free 7-Zip application that only takes a few seconds, here’s a demo:

check version windows

The steps on Windows are:

  1. Right-click on the TWBX and choose 7-Zip->Open Archive.
  2. Right-click on the .twb and choose View.
  3. Find the <workbook> tag and version attribute.
  4. Close the window.

That inspired me to figure out an equivalent on the Mac. I use BBEdit for my text editor (BareBones also offers a free text editor called TextWrangler that can do the same thing) and BBEdit natively supports zip files. It turns out I can just drag the TWBX onto the BBEdit icon on the dock and BBEdit will open up the zip file:

check version mac

The steps on Mac are:

  1. Drag the TWBX to the BBEdit or TextWrangler icon.
  2. Click on the .twb.
  3. Find the <workbook> tag and version attribute.
  4. Close the window.

This will easily save me hours over the course of a year, thanks, Shawn! There’s also a feature request for making version-checking easier that you can vote up. Also, if you’d like to change the version of the file you can edit that yourself, or (if you’re ok running the workbook XML through a web-based tool) using Jeffrey Shaffer’s Tableau File Conversion Utility.

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TRIMMEAN() in Tableau

Excel’s TRIMMEAN() function can be quite useful at removing outliers, essentially it removes the top and bottom Nth percent of values and then computes the mean of the rest. Here’s the equivalent formula in Tableau that in Superstore Sales computes the TRIMMEAN() of sales at the customer level removing the top and bottom 5th percentile of customers when used with the AVG() aggregation:

{FIXED [Customer Name]: SUM(
    IF {FIXED [Customer Name] : SUM([Sales])} < 
    {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .95)}
    AND {FIXED [Customer Name] : SUM([Sales])} > 
    {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .05)} THEN
       [Sales]
    END)
}

Read on for how to build and validate your own TRIMMEAN() equivalent in Tableau.

When building out calculations in Tableau I try to let Tableau do as much of the computation as possible for both the calculations and the validation, so I’m typing as little as I can. Starting with Superstore, let’s identify the top and bottom 5th percentiles, here’s a view using a reference distribution:

Screen Shot 2016-07-12 at 3.57.38 PM

Now we know what we’re going to have to remove. The next step is to duplicate this worksheet as a crosstab, then build out calcs that can return the 5th and 95th percentiles of Sales at the Customer Name level. While this can be done with table calculations (here’s an example from the Tableau forums) I’m going to use FIXED Level of Detail Expressions so I’ve got a dimension I can use, so for example I could compare the trimmed group to the non-trimmed group. Here’s the 95th percentile Level of Detail Expression:

{FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .95)}

The inner LOD is calculating the sales at the Customer level, then the outer LOD is returning the 95th percentile as a record level value. Here’s the two calcs which have values that compare to the reference lines above:

Screen Shot 2016-07-12 at 4.03.46 PM

The next step is to filter out the values outside of the desired range, here’s the TRIMMEAN Filter formula:

{FIXED [Customer Name] : SUM([Sales])} < 
    {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .95)}
AND {FIXED [Customer Name] : SUM([Sales])} > 
    {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .05)}

This uses the 5th and 95th percentile formulas and only returns True when the Customer level sales is less than the 95th percentile or greater than the 5th percentile, we can visually validate it by dropping it on the Color Shelf:

Screen Shot 2016-07-12 at 4.06.37 PM

Now that we have this the next step is to calculate what the trimmed mean would be. Again, we can use a view with a reference line, this time it’s been filtered using the TRIMMEAN Filter calc and the reference line is an average:

Screen Shot 2016-07-12 at 4.08.16 PM

Now we can embed the TRIMMEAN Filter formula inside an IF/THEN statement to only return the sales for the filtered values, this is the Trimmed Sales calc:

IF {FIXED [Customer Name] : SUM([Sales])} < 
   {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .95)}
AND {FIXED [Customer Name] : SUM([Sales])} > 
   {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .05)} THEN
   [Sales]
END

And here it is in the workout view, only returning the sales for the trimmed customers:

Screen Shot 2016-07-12 at 4.15.36 PM

Now that we have the trimmed sales there are two ways we can go. If we want the trimmed mean without the Customer Name in the Level of Detail then we can validate that in our workout view by using Tableau’s two-pass Grand Totals to get the average of the customer-level trimmed sales. This was created by:

  1. Removing the TRIMMEAN Filter pill from Colors (this increases the vizLOD and is no longer necessary).
  2. Clicking on the Analytics tab.
  3. Dragging out a Column Grand Total.
  4. Right-clicking the SUM(Trimmed Sales) pill on Measure Values and setting Total Using->Average.

Scrolling down to the bottom we can see that the overall trimmed mean matches of 2,600.79 matches the one from the reference line.

Screen Shot 2016-07-12 at 4.20.33 PM

Note that we could have used the Summary Card instead, however using the Grand Total lets us see exact values.

There’s a problem, though, if we use the Trimmed Sales all on its own in a view it breaks, whether using SUM() or AVG():

Screen Shot 2016-07-12 at 4.25.49 PM

The reason why is that the Trimmed Sales is a record level value and Superstore is at the level of detail of individual order items, but we’re trying to compute the trimmed mean across Customer Names. For the true trimmed mean in this case we need to aggregate this trimmed sales to the Customer Name like we did in the workout view, here’s the Trimmed Sales (Customer Level) formula that uses the Trimmed Sales and wraps that in an LOD to get the Customer Level sales:

{FIXED [Customer Name]: SUM(
    IF {FIXED [Customer Name] : SUM([Sales])} < 
    {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .95)}
    AND {FIXED [Customer Name] : SUM([Sales])} > 
    {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .05)} THEN
       [Sales]
    END)
}

This returns the same results in the workout view:

Screen Shot 2016-07-12 at 4.31.49 PM

And works all on its own in a view:

Screen Shot 2016-07-12 at 4.32.32 PM

Now this is a case where the FIXED level of detail expression is returning different results depending on the level of detail of the view, if we want it to return the same result then we can wrap all that in one more LOD expression, this is the TRIMMEAN Fixed calculation:

{FIXED : AVG(
    {FIXED [Customer Name]: SUM(
        IF {FIXED [Customer Name] : SUM([Sales])} < 
        {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .95)}
        AND {FIXED [Customer Name] : SUM([Sales])} > 
        {FIXED : PERCENTILE({FIXED [Customer Name] : SUM([Sales])}, .05)} THEN
            [Sales]
        END)
    })
}

And here it is in the workout view and a view without any dimensions:

Screen Shot 2016-07-12 at 4.34.36 PM

Screen Shot 2016-07-12 at 4.35.35 PM

 

 

Final Comments

This is a good (and bad) example of how Tableau is different from Excel. In one bad sense note that I didn’t parameterize the percentage for the trimmed mean, this is because in Tableau it would require two parameters because we can’t put calculations as the arguments to the PERCENTILE() function. In another bad sense the calculation requires understanding Level of Detail expressions and is not wrapped into a simple formula. On the other hand we’ve got very precise control over what the calculation is computing over with those Level of Detail expressions and aren’t just limited to doing trimmed means, we could do trimmed medians, get the Nth percentile of the trimmed values, etc.

Here’s the trimmed mean workbook on Tableau Public.

Screen Shot 2016-07-08 at 4.02.54 PM

Parallel Coordinates via Pivot and LOD Expressions

Parallel coordinates are a useful chart type for comparing a number of variables at once across a dimension. They aren’t a native chart type in Tableau, but have been built at different times, here’s one by Joe Mako that I use in this post for the data and basic chart. The data is a set of vehicle attributes from the 1970s, I first saw it used in this post from Robert Kosara. This post updates the method Joe used with two enhancements that make the parallel coordinates plot easier to create and more extensible, namely pivot and Level of Detail Expressions.

The major challenge in creating a parallel coordinates chart is getting all the ranges of data for each variable into a common scale. The easiest away to do this is to linearly scale each measure to a range from 0-1, the equation is of the form (x – min(x))/(max(x)-min(x)). Once that scale is made then laying out the viz only needs 4 pills to get the initial chart:

Screen Shot 2016-07-08 at 3.25.20 PM

The Category is a dimension holding the different variables, ID identifies the different cars in this case, the Value Scaled is the scaled measure that draws the axis. Value Scaled is hidden in the tooltips while Value is used in the tooltips.

Where this is easier to create is using Tableau’s pivot function, in Joe’s original version the data is in a “wide” format like this:

Screen Shot 2016-07-08 at 3.20.33 PMSo for each of the measures a calculation had to be built, and then the view was built using Measure Names and Measure Values:

Screen Shot 2016-07-08 at 3.47.05 PM

The major limitation here is in the tooltips (in fact, Joe had rightly hidden them in the original, they were so useless):

Screen Shot 2016-07-08 at 3.33.36 PM

The tooltip is showing the scaled value, not the actual value of acceleration. This is a limitation of Tableau’s Measure Names/Measure Values pills…If I put the other measures on the tooltip then I see all of them for every measure and it’s harder to identify the one I’m looking at. Plus axis ranges are harder to describe.

Pivoting Makes A Dimension

I think of Tableau’s Measure Names as a form of pivoting the data, to create a faux dimension. I write faux because beyond the limits mentioned above we can’t group Measure Names, we can’d blend on Measure Names, we can’t do cascading filters on Measure Names, etc. The workaround is to pivot our data so we turn those columns of measures into rows and get an actual “Pivot field names” dimension (renamed to Category in my case) and a single “Pivot field values” measure (renamed to Value in my case):

Screen Shot 2016-07-08 at 3.45.22 PM

Then for the scaling we can use a single calculation (instead of one for every original column), here’s the Value Scaled measure’s formula:

([Value] - {EXCLUDE [ID] : MIN([Value])})/
({EXCLUDE [ID] : MAX([Value])} - {EXCLUDE [ID] : MIN([Value])})

I used an EXCLUDE Level of Detail Expression here rather than a TOTAL() table calculation as an example of how we can use LODs to replace table calculations and have a simpler view because we don’t have to set the compute using of the table calculation.

Now with a real Category dimension in the view the Value Scaled calc is computed for each Category & ID, and this also means that if we put the Value measure in the view then that is computed for each Category & ID as well, immediately leading to more usable tooltips:

Screen Shot 2016-07-08 at 3.55.53 PM

For a quick interactive analysis this view takes just a couple of minutes to set up and the insights can be well worth the effort. Prior to the existence of Pivot and LOD expressions this view would have taken several times as long to create, so for me this revised method takes this chart type from “do I want to?” to “why not??”

Cleaning Up

To put this on a dashboard some further cleanup and additions are necessary. Identifying the axis ranges is something that is easier as well with the pivoted data. In this case I used a table calculation to identify the bottom and top-most marks in each axis and used that as mark labels to identify the axis range:

Screen Shot 2016-07-08 at 3.58.04 PM

The Value for Label calculation has the formula:

IF FIRST()==0 OR LAST()==0 THEN
    SUM([Value])
END

The addressing is an advanced Compute Using so that it identifies the very first or last mark in each Category based on the value:

Screen Shot 2016-07-08 at 4.01.00 PM

In addition I created two different versions of the value pill that each had different number formatting and used those on the tooltips, used Joe’s original parameters for setting the color and sort order with revised calculations (which were also easier to use since Category is a dimension), and finally added a couple of other worksheets to be the target of a Filter Action to show details of the vehicle:
Screen Shot 2016-07-08 at 4.02.54 PM

Click on the image above to download the workbook from Tableau Public.

Screen Shot 2016-06-30 at 2.36.54 PM

Sorting a Dimension by Two Values At Once

I recently got a question via email about how to sort a view by two different criteria at the same time. Here’s an Excel table of opportunities where for each month and Opportunity ID there’s a forecast of size of opportunity:

Screen Shot 2016-06-30 at 2.12.45 PM

The goal here is to sort the opportunities within each account type by the nearest (by month) and biggest opportunities (by Forecast size) first, so it looks more like this in Tableau:

Screen Shot 2016-06-30 at 2.13.38 PM

Now with that data in Excel arranged in a tabular form I can sort on December, then November, then October, and so on, and get the desired sort:

Screen Shot 2016-06-30 at 2.14.29 PM

But in Tableau I can’t do that, if I try to work with the data in that “wide” format with a column for each month it just won’t work. If I use Tableau’s pivot feature to make the data “tall” with a record for each Opportunity ID and Month then I still run into problems. I want to sort the opportunities by each month and by Forecast but when I try to sort the Opportunity ID dimension I can’t get it to work, it only sorts by a single month’s values, so in the view below Opportunity ID 864280 should be the first new one for August since:

Screen Shot 2016-06-30 at 2.15.31 PM

The Excel way isn’t good because each month I have to manually re-sort the data. And in Tableau it just seems impossible to get the right sort because it looks like we need to sort in two different directions at once (get the earliest non-zero month for each opportunity, and then sort up and down the opportunities in each account type), and Tableau only lets us sort on one thing at a time. However, it is possible – read on for how to get this kind of sort in Tableau and maybe learn a few math tricks!

Part of how this kind of problem can be more challenging is the way the problem (and data) is initially presented to us. When we see the data in the crosstab form in Tableau the *appearance* is that we need to sort in two different directions. In fact, we really only need to sort in one direction based on the forecast value in the first month for each opportunity, so in the view below we’d want Opportunity ID 864271 to be the first one sorted because it’s from July 2016.

Screen Shot 2016-06-30 at 2.16.45 PM

Each opportunity row in the view needs to be sorted within the account type by the first (earliest) month where there is a non-zero forecast and then by the value of Forecast in descending order for that month.

The key to sorting headers and panes in Tableau is that it’s done using the discrete (blue) pills on Rows or Columns from left to right. So the left-most discrete (blue) pill headers are sorted, then the 2nd discrete pill’s headers are sorted, and so on. For discrete dimensions from a primary source we can sort by a measure, use the default alphanumeric sort, or a manually, otherwise any discrete pills are by default alphanumerically sorted or manually sorted.

Therefore in this case I knew I needed to either return a measure that could sort some dimension (like the Opportunity ID) or return a discrete dimension value that with the default alphanumerical sort would work right. Note that filtering wouldn’t work here because the goal is to show a sorted crosstab.

The next part of working out the solution is how to structure this value for sorting. I’ve done some multi-level sorting in the past where I needed a nested sort of single dimension by two different criteria, and a common construct is a number of the form X.Y where the integer portion X is from one criteria and the decimal portion N is from the other criteria. So with the default alphanumerical sort 1.2 comes before 1.3 comes before 2.1 etc.

So for the integer part of the sort I need to convert the date for each opportunity into a number where the Forecast is greater than 0. The Date Number (temp) calc has the formula:

IF [Forecast] > 0 THEN
    INT([Date])
END

Screen Shot 2016-06-30 at 2.17.34 PM

This convers the date into an integer, in this case the number of days since 1/1/1900. To get the first (earliest) month for each opportunity then all I need to do is aggregate it with MIN() at the level of Opportunity ID:

Screen Shot 2016-06-30 at 2.18.01 PM

Ultimately, this is is what we’re going to do to get that pill sort of Opportunity ID’s in the final view.

For the decimal part of the sort I needed a number where the smallest numbers reflected the largest values, and it needed a value between 0 and 0.999999 (it can’t be a whole value of 1 because that would affect the integer sort). A way to turn a set of positive numbers into decimal numbers between 0 and 1 is to do X/(max X). In this case X is the Forecast, so to get the max X in the data I used the Level of Detail Expression, here’s the Max Forecast (temp) formula:

{FIXED : MAX([Forecast])}

Screen Shot 2016-06-30 at 2.18.35 PM

Now if I do [Forecast]/MAX([Forecast]) that’s going to return a number between 0 and 1 that preserves the original ordering of values, i.e. bigger values of Forecast are closer to 1. So to invert that I used use 1 – X/(max X). So if (max X) is 10 and X is 9, then the result of (1 – 9/10) is 0.1, while if X is 2 then the result of (1- 2/10) is 0.8, a bigger number.

We avoid results of 1 that could affect the sort by skipping values of where the Forecast is 0, here’s the Invert Forecast (temp) formula:

IF [Forecast] > 0 THEN
    1-[Forecast]/[LOD Max Forecast Value]
END

Screen Shot 2016-06-30 at 2.19.19 PM

I could have avoided the LOD expression for the max value by just setting a gigantically huge number, however past experience with foreign currencies has shown me that whatever huge number I can imagine is likely to be smaller than reality so I chose to make sure that the value is coming from the data

With all the values worked out I could now put everything together into a single calculation, this is the Sort calc that returns record-level values:

IF [Forecast] > 0 THEN
    INT([Date])
    + (1-[Forecast]/{FIXED : MAX([Forecast])})
//Forecast is 0, return a really big number that will be put at the end of the sort
ELSE
    999999
END

Screen Shot 2016-06-30 at 2.20.09 PM

This calc returns the numbers as record level values.

To show how the sort works out I set up this view where the Sort calc is used as the leftmost discrete dimension to show what gets sorted first, with the bar chart we can quickly visually verify that the dates are sorted with earliest months first and then by the Forecast within each month:

Screen Shot 2016-06-30 at 2.20.41 PM

Note that there’s a different value for each Opportunity ID/month combination, when what we really want is that single minimum value for each Opportunity ID/month. So we need to aggregate the Sort measure with MIN() at the level of detail of Opportunity ID, and we can do just that using a pill sort on the Opportunity ID dimension:

Screen Shot 2016-06-30 at 2.21.14 PM

Now we can arrange pills to build the original crosstab view and have the desired sort:

Screen Shot 2016-06-30 at 2.13.38 PM

And as the data updates the sort will automatically work, in this case I’ve added January 2017 to the data:

Screen Shot 2016-06-30 at 2.22.37 PM

Conclusion

The following bits of Tableau knowledge were necessary to get the desired results:

  • How Tableau sorts views using discrete pills.
  • How Tableau’s pill sorts work.
  • A tiny bit of Level of Detail Expression building.

And then the following math tricks were used:

  • Combining two different numbers into one using an integer number for one value and a decimal number for the second value.
  • Making positive numbers into a range of 0-1 using X/(max X). A different formula would be needed if there were negative numbers and/or the desired range was different.
  • Inverting ranges to make big numbers small and small numbers big using 1 – X/(max X)

FYI if LOD expressions are not available in your particular data source then you could use a table calculation, a data blend, or just manually enter your equivalent of the Max Forecast value. I set up a table calculation version as well in the Sorting by Two Values Tableau Public workbook.

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Show Me *All* The Numbers: Displaying Every Record for Too Tall Data

Here’s a sample data set with 4 records:

When we bring that data set into Tableau and build a text table, though, we only see 3 rows:

If we want to show all 4 underlying records as 4 rows in the Tableau text table we have to jump through a couple of hoops, the rest of this post describes why Tableau behaves that way and how to fix it.

The Data is Too Tall

There are all sorts of resources about working with data that is “too wide”, for example the old Preparing Excel Files for Analysis KB article, the new Pivot feature introduced in Tableau v9.0, or this post on Tiny Habits from Emily Kund with commentary from yours truly. Too wide data has too many columns for the kind of analysis that we want to use. There aren’t so many resources on “too tall” data, of which this is an excellent example.

To explain what “too tall” data is, let’s first look at the data:

What is the grain of this data? In other words, what combination of field(s) makes a unique record in the data?  We might be tempted to say Group, Color, and Size, but for Tableau there is no difference between the first two records:

Effectively the data has no unique grain. Yes, there’s a difference in position between these two records but that is not detectable by Tableau because record order (position) is not something stored in each record. This highlights something I talk about in my training classes: the difference in mental models between Tableau and WYSIWYG tools like Excel. Tableau approaches data as a database does, and the default behavior in databases is that record order doesn’t matter. The reason databases abstract record order away is to get higher performance.

So when we bring this data into Tableau and create a view Tableau’s default behavior is to aggregate the data to the level of the dimensions in the view (i.e. on all Shelves and the Marks Card except for Filters). Here’s what happens we bring all the fields in this data set into the view as dimensions:

There aren’t enough dimensions to separate out the two A/Red/Small records. This explains what I wrote earlier about the data lacking enough dimensionality. What we really need is another column (field) to identify the records. So we now have a simple definition:

  • “too tall” data has too few columns to effectively perform the analyses we want
  • “too wide” data has too many columns to do effectively perform the analysis we want

The rest of this post describes three ways to show all the records: Show Underlying data, editing the source, and constructing a specific Tableau view.

Do You Need to Show the Data in a View?

If you don’t need to show the data in a Tableau view users can still view the underlying data in both Tableau Desktop and from Tableau Server & Online. Here’s the underlying data in Tableau Desktop:

And on Tableau Server:

So some user education might be all you need to show all the records. If the data is too tall and you do have to show a view with all the records then you can alter the source data or set it up in Tableau.

Do You Control the SpiceSource?

If you have control over the source data then many sources have features to add a unique record identifier that would add that necessary column to make the data not too tall, not too wide, but just right. For example Excel has the ROW() function:


Creating a view with this that shows every record is trivial, we just need to add Row ID as a dimension:

If you’re not using Excel then you’ll need to look for a function that adds a row ID, record ID, etc. Part of why this is a rare problem is that most relational data tables are set up with unique keys (indexes) that give us those unique values to draw tables. Where I typically see too tall data coming from is from hand-entered data sources and ancient systems.

When you don’t have that option and you’re stuck with too tall data we can still get a view showing every record in Tableau.

Building a Tableau View Showing Every Record for Too Tall Data

There are three main steps to building a view to show every record:

  1. Turning off aggregation so Tableau will return every record from the data source.
  2. Creating a table calculation to increment over each record and provide a unique identifier.
  3. Using that table calculation as a discrete pill to sort the view.

Here’s how using the above data source:

  1. Turn off Analysis->Aggregate Measures:

    The view now looks like this:

    The reason why there’s a lot of white space is that Tableau is now returning multiple records (the two 1’s) for A/Red/Small and has turned on Mark Stacking by default. This is not a problem, we’ll be rearranging the view later on to get rid of Mark Stacking.
  2. Create a Rank calculated field with the following formula:
    RANK_UNIQUE(MIN([Number of Records]))

    I use RANK_UNIQUE() here instead of INDEX() because rank only counts non-Null values and should there be any unwanted densification those ranks will return Null, whereas INDEX() would return values that would throw off the desired ordering.

  3. Drag the Rank field to the Level of Detail Shelf and set the Compute Using to an Advanced… Compute Using where all the dimensions are used for addressing in the order that you want the records to appear:

    Something I’ll typically do at this point to validate is to add the table calc (Rank) to the text Shelf or Measure Values (here I have it on text):
    And we can see that the Rank is accurate.
  4. Turn Rank into a discrete (blue) pill:
  5. Drag Rank to the Rows Shelf to the left of all the dimensions. With the unique identifier for each record (mark) the Mark Stacking goes away:
  6. As the last step turn off Show Headers for the Rank pill:

    The view now shows each individual record:

Conclusion

Tableau is designed to help us dive & swoop through thousands/millions/billions of rows of data to discover insights so Tableau’s default behavior is to aggregate the data. Tack on Tableau’s mental model of treating data as a database does and a task like showing every record can be more complicated when the data source isn’t aware of more modern database concepts and lacks the necessary dimensions to uniquely identify each record. A feature request for row numbering has been created to make this easier, vote it up if this is something that interests you!

Here’s a link to the too tall workbook on Tableau Public.