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# The Data School Blog

## How to build a linear trendline for calculations

One of the analytical features that Tableau offers is the capability to build a trendline with just a couple of clicks. However, trendlines in Tableau do have some limitations, among them is that you can’t use them within your calculations. This becomes especially troublesome if, for example, you want to calculate the distance to the trendline or do any other calculation that interacts with the trendline.

## How to make a correlation matrix in Tableau

A correlation matrix is handy for summarising and visualising the strength of relationships between continuous variables. Essentially, a correlation matrix is a grid of values that quantify the association between every possible pair of variables that you want to...

## Successful Data School Client Projects

During our time at the Data School, we have about 8, week-long client projects. We get the brief and data on a Monday and then have to present our findings on the Friday afternoon. After presenting we then have a feedback session with the coaches and hopefully improve...

## The 5 Most Useful Things I’ve Learned in Tableau Since Joining the Data School

Before joining the Data School I knew very little about Tableau. There were some things I knew how to do but often didn't understand why or how these things worked. Since joining the Data School I've learnt many new techniques and theory which helps me understand and...

## The Prep Off: Alteryx vs Tableau Prep Round 2

Two major contenders in the ring tonight: new but developing at light speed, Tableau Prep and tried and trusted, Alteryx Designer.Who will win this time after a draw in the last Prep Off? Watch the replay of Round 1 here. How do these two softwares compare when...

This blog provides the answers to the Tableau set action tasks found here. Proportional Highlighting Create the two sheets, segment by sales and sub-category by sales.Right click the segment dimension and create a set.Place the segment set on the colour card in the...

Tableau's set actions allow you to make your dashboard or worksheet interactive. By hovering, clicking and generally interacting with the elements on a sheet colours, sizes marks and may more things can be influenced on both the same and other charts. Set actions...

## Are you sure you need a dual-axis?

Let’s say that you wanted to have two measure values on one graph and to colour by these measures as well as have lines with different thickness. Prior to last week I thought it would be necessary to use a dual-axis chart for this which was a frustration as this means...

## Tableau’s Order of Operations

Order of Operations To understand how Tableau works it is useful to know the order in which it manipulates and filters data when producing your view. This process is called the order of operations. It helps to know the order of operations so you can use it to your...

## Colouring using a Parameter

In this blog post I will be talking through the steps to making a line chart in which the colour of the line is controlled by a parameter. This can be useful when you want to show all values for context but don't want too many colours and feel a different colour would...

## Using the Detour tool in Alteryx

An introduction to the detour tool in Alteryx and how it can be used to create a macro suite.

## Tableau Dateparts vs Datevalues

Dates in Tableau will behave differently depending on whether they are a datepart (blue) or a datevalue (green). This affects how the axes display/behave and also how visualisations such as line charts will display. The difference essentially boils down to dateparts...

## Why You Should Apply For The Data School

Now that DS11 are approaching the end of our 4 months of training at the Data School and will soon be shipped off to our first of 4 placements, I have been reflecting on the experience and would like to convince you to apply for the Data School too.   Because...

## Tableau Tip – Setting up automatically updating views that compare year to date performance

Something we learnt last week was how to set up a chart which will compare any given measure for the current year to date (YTD) with the previous YTD. This is a really useful tip which has many use cases, especially in a business sense. We are constantly looking to...

## Creating effective sparklines which highlight weekly change

A sparkline is a very small chart used to show snippet trends of data such as, stock market price, seasonal changes or highlighting maximum and minimum values. Usually they are drawn with no axis and just present the general shape of a trend. I used sparklines for the...

## Dashboard Formatting With Containers in Tableau

Before joining the Data School dashboard formatting was a nightmare. I thought that the sizing and position of things relied on the eye alone and would spent ages resizing things and trying to make them align in an aesthetically pleasing way. Since learning about...

## My Project Manager Experience

PROJECT MANAGER (PM) EXPERIENCE AND TIPS FOR FUTURE DATA SCHOOLERS   On my 7th week at the Data School, I was Project Manager for DS12. It was DS12's second client project for MOO Business Services (MBS). The total time that DS12 were given during that week for...

## Alteryx Core Exam Tips

The Alteryx Core exam is a very good way to test your Alteryx skills and also learn some new information that would usually be glossed over. The exam can be registered for here and at the start of the next month you will receive an email with a link that allows you to...

## Tableau QA Revision Tips

Tableau QA Exam Tips The Tableau QA Exam can be a little intimidating, but there are lots of resources out there from the community and Tableau itself to help you pass the certification. Here I will go through some of the things I found most useful in preparing for...

The Data School not only trains us in Tableau and Alteryx, but also give us a chance to develop other skills like presenting, writing and working with clients. In addition to this, in the last month of our DS time ahead of our placements we shadow a member of the...

## Organising your Tableau Data Pane for Bliss and Harmony

Today DS11 and DS12 were treated to a talk from Simon Beaumont about data architecture, enabling customers to understand your dashboards, how to make your workbooks easy for others to pick up and more. In this post, I will go over a few things about organising your...

## Using Alteryx to Append Fields with a Lookup Table

While attempting the recent NHL Makeover Monday, I decided to supplement the attendance data with stadium capacity data. I found some data that would work and after some quick cleaning of the data set, added it to the NHL data on Tableau. I ended up with a lot of null...

## Tableau’s ‘Replace References’ feature

I feel an urgent need to blog about a simple feature in Tableau that just potentially saved me from hours of retrospective code-amending and checking. My almost nightmare Let me start with some context. I've spent the last few days exploring a dataset in Tableau and...

## Structuring Word Clouds

Word clouds don't have the best rep, but they can be a powerful tool to represent text-based data. There are tons of great manuals for how to build a word cloud in Tableau, so I won't get into the details about that here. One thing I will say is that with word clouds,...

## How to Prepare for your Alteryx Designer Core Exam

This month, many of DS11 are taking the Alteryx Designer Core Exam (as well as the Tableau QA), including myself. If you're interested in my top tips on how to pass the Tableau QA, see my post here  In this post, I will go through: The resources I found helpful while...

## How to Teach Tableau/Alteryx : Louise’s Experience

Last month, DS11 taught the public Tableau and Alteryx and this month, we are conducting webinars teaching the same content. Check out our meetup page for more details on upcoming webinars and events! For both of these lessons, I taught Alteryx Data Prep. If you...

## Diego’s journal (DS12) – Week Four

The week went very fast and it felt a bit like those small recap episodes between the seasons of a TV program. However, it was still challenging as we were introduced to Tableau Intermediate and very important concepts such as LODs, Table Calcs and Order of Operations.

## Web Scraping JavaScript Content

Introduction Web scraping is an extremely powerful method for obtaining data that is hosted on the web. In its simplest form, web scraping involves accessing the HTML code (the foundational programming language on which websites are built) of a given website, and...

## How to Approach Analysis & Design Dashboards

Coach Andy and Coach Carl take you through tips on how to Investigate new data sets, laying out a dashboard, and working with containers

## Running Sum and Moving Average in SQL

Using Tableau's Superstore as the database, the SQL query: Select [Region], [Order Date], Sum([Sales]) as 'Sales' From superstore Group By Region, [Order Date] ; creates a table with column headers Region, Order Date and Sales, where the Sales is the sum of sales for...

## Colour Conditions in Tableau

For this topic, I will be using the Makeover Monday ’19 Week 1 NHL dataset.   I had produced a very simple dashboard that compares the Home Attendance and Road Attendance for every NHL team, filtering by each season. The chart shown in my dashboard is a butterfly...

## Line of Best Fit

When you go to the analytics tab and drag the trend line onto your scatterplot Tableau creates a line going through your plots. But what is it doing and what do the figures mean? When plotting a linear trend line Tableau uses the equation y=ax+b In this equation a is...

## Using YoY change to colour shapes on a line chart

The final Makeover Monday of 2018 was on the average annual Christmas spending in the US. All that was provided was the year and the average spend for that year, although it may seem simple, there were many different takes on this as you can see online. For my viz...

## A Tableau Visualisation of the Whole American Civil War

Over the holidays I finally had some time to pursue a passion project that had been on the back of my mind for some time. Being somewhat of a history buff, I have a great interest in the American Civil War, and I wanted to create a Tableau visualisation using data...

## Chaining apps in Alteryx

I hit a wall in my previous post when trying to dynamically update a drop down interface tool with the field names of a given input dataset. The issue was that if the field names in the incoming dataset were different to the field names of the dataset that I built my...

## My Experience of the Tableau Desktop QA Exam

Excitingly, I got to start 2019 as a Tableau Desktop Qualified Associate! I prepped for the exam over Christmas and took it on the morning of New Years Eve. In this post I will take you through how I approached the exam prep, as well as my experience of the exam...

## Tableau Tip // Creating YTD metrics on a KPI Dashboard

Using Key Performance Indicators (KPIs) in a dashboard are a great way to give a quick indication of how an organisation is doing. This would be actual number of say sales, or number of people donating to a charity, as well as how these metrics change over time....

## Why Colours Matter

Using colour in your viz adds another dimension that can ascend your dashboard from average to amazing or burn your audience’s retinas. Colour allows you to direct your audience’s attention or gloss over background information. It can be used to invoke emotion, set a...

## Tableau : Behind the scenes

Using Tableau on a regular basis, dragging and dropping pills all around, we easily forget that is it not as simple and what the machine does behind the scene.

## Tableau Tip: Watch Out for Misleading Average Lines!

Tableau's Analytics pane allows you to slap an average line onto your view. Drag, drop, done? Not quite. In this blog, I will show you an example of when the average line Tableau creates for you may not be doing what you think it does.   Let's start So Figure 1...

## Dynamically Controlled Bins

When we work with data, our continuous data (such as sales or profit) it is usually grouped under some categorical field. Normally these fields would be our discrete variables in the data set, such as “Country” or “Category”. Nevertheless, sometimes we would like to group our data under numerical ranges, this is when we would create a bin based in a numeric dimension.

## Comparing The Proportion Of Products Sold Across Regions

In some cases companies may be looking to compare and contrast how a set of products are selling across a number of regions or stores. Allowing the identification of individual products that stand out per region and thus take action accordingly. To create this we will...

## LODs vs Table Calcs: How to compare the profits of all the Sub-categories to that of the selected one?

In this example, we are going to look at two different ways to get the same result in Tableau. Follow along using Tableau's Superstore dataset.     Look at the screenshot above. It's the final result that we want to achieve. We want to compare the profit of each...

## Calculating Amount of Days from First Entry

In this blog we will use an LOD to calculate the first entry date of purchase of products in the Superstore data set and then use this LOD to calculate the running sum of sales over amount of days after the first sale. This normalises the start of selling for...

## Using LODs to Calculate Customer Retention

This post looks at how we can display what percentage of customers is made up of return customers, and what percentage is new customers. To achieve this, I'm using Level of Detail expressions to essentially create bins of customers, depending on when they placed their...

## Tableau MIN(Date) LOD’s – Use Cases

Tableau LOD's can be used to get the date of first purchase, first signed up, first order etc. This has many real world applications such as tracking percentage difference from this first date, looking at customer retention from first date and seeing how long it...

## Louise’s 2018 in Data

This time last year, I was a final year Medical Engineering student without a clear career path. Now, I've graduated and I have a job that I love - more than I expected to have by this time!     2018 has been an amazing year and I'd like to take a moment to...

## Alteryx tips: Joins, wrong choice of tools, and how to prevent costly mistakes

There is one thing I am really scared of: joins.  Whenever we have a weekly project (and even during Dashboard Week), I am always very careful when joining multiple files together. There are even vizzes on Tableau Public to guide you on how the different types of...

## Web Scraping 101: A guided example in Alteryx – Part 1

Which tools do you need? The web offers several tools that you can use. However, here we are going to use Alteryx. You don’t have Alteryx and would like to try it? Install the trial version here. Are you a student or an academic? Do you work in the nonprofit sector?...

## Web Scraping 101: A short introduction

What is web-scraping? Web-scraping is the automated collection of information from webpages.   The authors of “Automated Collection with R. A Practical Guide to Webscraping and Text Mining” explain the process very clearly: “The Web consists predominantly of...

## Common Baseline Graph With Parameter (Part 2)

In the first step, I have shown how to create a common baseline graph. Here I will show you how to use parameters to make this graph more dynamic. We will use a parameter control to highlight a chosen subcategory and create a dual axis which will create a large...

## Creating a Common Baseline Chart (Part 1)

A common baseline chart will allow you to create a view which will show each dimension starting at the same time to compare their overall trend. From each product’s beginning to end. For example, you could use this chart if you wanted to see how much each product has...

## How to Prepare for your Tableau Specialist or Qualified Associate Exam

I passed the Tableau Desktop Qualified Associate exam today! 😀   In this post, I will go through: The resources I found helpful while preparing for the exam My experience of taking the exam My top tips for passing!   What types of Tableau certifications are...

## 2018 Data Reflections

2018 has been a big year for me, data wise, so I thought it was apt to reflect back before moving forward with some goals into 2019. This seemed especially relevant today, given that I've just passed the Tableau QA Exam! Like my half way through blog, this will...

## Diego’s journal (DS12) – Week Three

During week three we went back to ETL, starting with a deep dive in Tableau Prep followed by a very intensive couple of days learning Alteryx Macros. We finished our week with an introduction to statistics in data visualisation and the different tools that Tableau and Alteryx provide to do descriptive and inferential analytics. One of the different things about week three was that we didn’t have any class with our usual coaches (Carl and Andy) but previous Data Schoolers who now work with the Core Team.

## How to create a Gantt Chart in Tableau

In this post, I'll take you through how to create a Gantt chart. This is a useful chart that shows the duration of events, e.g. delivery times or hospital wait times. The date field is usually on the column, and then the various dimensions are on the rows. I'll be...

## Tableau: Creating a customer drop-off tracker

Tracking the rate of your customers' orders so that you can react if a customer appears to be dropping off   A few weeks ago I built a rudimentary customer drop off tracker for a client project and I thought I'd share the technique. It relies on finding the...

## Alteryx stats tools for beginners: part 5 – Time series analysis

Alteryx stats tools for beginners This is part three of a five part series introducing the stats tools available in Alteryx explaining the tools and indicating when their use is appropriate. Clustering Data investigation Regression analysis Classification Time Series...

## Alteryx stats tools for beginners: part 4 – Classification

Alteryx stats tools for beginners This is part four of a five part series introducing the stats tools available in Alteryx explaining the tools and indicating when their use is appropriate. Clustering Data investigation Regression analysis Classification Time Series...

## Dashboard Week Finishing Touches

With some time free over Christmas I decided to look over my vizzes from Dashboard week with a fresher pair of eyes and fix some things that were annoying me. New York City Snowploughs Day ones snow ploughing dashboard was my least favourite of the week and I didn't...

## Alteryx stats tools for beginners: part 3 – Regression analysis

Alteryx stats tools for beginners This is part three of a five part series introducing the stats tools available in Alteryx explaining the tools and indicating when their use is appropriate. Clustering Data investigation Regression analysis Classification Time Series...

## Dashboard Week Day 5: Boy Bands

For Dashboard week day 5 we were given a dataset on boy bands. The data contained the highest charting single, dated when it charted highest, for every boy band. It also contained information about every boy band member such as height, hair style and hair colour. We...

## Adding Test Conditions to a Standard Macro

One of the topics covered by DS12 this week has been macros which included learning the difference between standard, iterative and batch macros. We also briefly delved into the world of apps. I wouldn't really consider myself the most tech-savvy person so finding out...

## Dashboard Week – A Summary

It is the start of the week after dashboard week, this new week is one of festive joy rather than anticipation for what curve balls Andy could throw at us. During these moments of calm, I wanted to reflect on what I have learnt from last week's madness. The week...

## Tableau Tip: Stop Your Viz In Tooltips From Being Filtered

For Dashboard Week Day 4, we looked at Seattle cycling data (see my blog here). I decided to incorporate Viz in Tooltips to enhance my infographic (Tableau Public here) and give the reader more context (see Figure 1). Now I don't often use Viz in Tooltips because I've...

## How to make a Dynamic Tooltip

Dynamic Tooltips   For this topic I am looking into the average adjusted inflation gross versus budget for each of the Disney Renaissance films. Link to dataset.   A dynamic tooltip provides Tableau users a little more flexibility in what they would like to...

## Dashboard Week Day 5 – Boy bands! Backstreet’s Back

The blog comes to you a few days late, Friday was a blur of a day in which I did not get to write this post. But here it is, the final day of dashboard week, the boys and the bands, a dashboard all about boy bands, their members and accomplishments. We started the day...

## DS11 Dashboard Week // Day Five: Boy Bands

The final day of our dashboard week was so fun! We got a cheeky hint from Andy on Thursday evening with a gif featuring the BackStreet Boys.   He then announced, via his blog of course, that we were to analyse data about Boy Bands from the Internet Boy Band...

## DS11 Dashboard Week Day 5: Boyz Boyz Boyz!

This is going to be a short one since it's been a long week and quite frankly, there is notv all that much to say about what I have created today. Still, it has been a great last day of a long week full of excitement, frustration, satisfaction and tons of lessons...

## Dashboard Week Day 5: Internet Boy Bands Database

It’s the last day of Dashboard Week before the Christmas break and DS11 has to visualize the Internet Boy Bands database. This should be fun!

## Creating control charts in Tableau

Control charts are a great way to quickly visualise outliers or significant values in an analysis. Learn how to create them in Tableau by following the instructions in this blog.

## Dashboard Week ~ Day 4! Time to talk about Seattle bike…counters!

Dashboard Week, Day 4. I loved this one! Here's Andy's blog post. Bikes, bikes, so many bikes Let me start by saying this: as soon as I arrived in London, the first thing I bought was a bike. I hadn't even gone shopping at a supermarket yet and I already had a bike....

## DS11 Dashboard Week Day 4: I Want to Ride my…

After our excursion into the new, eciting, sometimes confusing, often just plain wierd world of Power BI, we were back in our native Tableau for our second to last Dashboard Week Challenge. This was another data set from the US (it's like nothing interesting ever...

## Dashboard Week: #3 A Summary of Seattle Bike Counters

Day 4 of dashboard week has now arrived and we were greeted with a set of cycling traffic data for a number of routes in Seattle, the analysis of such data is extremely important due to the significant levels of investment to create new cycle lanes throughout Seattle...

## Dashboard Week Day 4: Seattle Bike Count Summary

For day 4 of Dashboard week we had to analyse data from Seattle bike counters at various routes through the city. I produced a summary report kind of dashboard which looked into the difference in bike usage between weekdays and the weekend. Bikes were used much more...

## Dashboard Week Day 4 : Seattle, i.e. Cyclist Heaven

It's day 4 of dashboard week and I am starting to fatigue. No matter! We push on.   The Challenge Today's dataset counts the number of cyclists riding through the roads of Seattle. Potentially very interesting for a Seattleite (/satellites) or a keen cyclist. For...

## Dashboard Week Day #4

Today Andy set us the task of visualising some data about bike traffic around Seattle. The data comes from about 13 spots around the city where bike traffic is measured. I had a clear idea of what I wanted to achieve in the day. I wanted to make a coxcomb chart, the...

## Creating control charts in Tableau using window calculations and parameters

Follow this step by step guide, to learn how to make a control chart in Tableau

## Dashboard Week Day 4 – Bicycles in Seattle

Once again we started off the day by presenting our dashboards from the previous days, everyone got to proudly show off their Power BI creations! I showed off my dash about where the foreign monetary gifts were coming from and going to....

## DS11 Dashboard Week // Day Four: Seattle’s Cyclists

Day four's challenge was back in Tableau - analysing count of cyclists from Seattle's Open Gov data. Over the past four or five years Seattle have implemented counters to track the number of cyclists over time in various parts of the city. This is because there are...

## Dashboard Week Day 4: Seattle Bike Counters

For dashboard week day 4, DS11 will analyze data from the City of Seattle to understand cycling traffic at three cycle counters around the city.

## Dashboard Week: #3 The Flow of Gift Aid To American Universities

Day 3 began (as per usual in dashboard week) by presenting the visualizations we created the previous day to Andy and the rest of our cohort for feedback. Once all presentations had been made the challenge for today was revealed. With a wince we all read the list of...

## Dashboard Week ~ Day 3: Want to learn Power BI?

Day 3 of Dashboard Week is almost over! And we've finally discovered what Andy had meant by "Wednesday is going to be interesting". Today is the day of...Microsoft Power BI!   Do you know all Microsoft products?   If you have a look at Microsoft's main page, Power BI...

## DS 11 Dashboard Week Day 3: I Got the Power

Try Something New! It was hump day for DS11's dashboard week today, reason enough for Andy to mix things up a little and drag us (some of us willingly, some less so) out of our comfort zone. The task for today was to visualise a data set on money paid to US higher...

## Dashboard Week – Day 3

Today’s task required us to use Power BI for the First time. It only took 15 minutes within using the tool did I become a fan. I find it easy to build different chart types without having to create any complicated calculations (depending on what you want to...

## DS11 Dashboard Week // Day Three: Foreign Gifts in Power BI

This morning marks the mid-week day of our dashboard week and I was feeling just about comfortable with the format: understand the data, clean the data, explore and visualise in Tableau. However, Andy threw a curve ball in this morning and one of the rules for day...

## Dashboard Week Day 3 : Power BI for noobs

SPOILER ALERT: I like Power BI. Of course it has pros and cons, but overall, not too shabby.     Woah, we're half way there! Woahhhhh! It's day 3 of Dashboard week which means we're at the halfway point! See my viz from yesterday here. Last night, Andy...

## Dashboard Week Day 3: Foreign Gifts to American Universities with Power BI

For day 3 of Dashboard week we were given the task of using Power BI to analyse financial gifts to American Educational Institutions from foreign sources. Using Power BI was an enjoyable challenge and was useful in illuminating its similarities and differences to...

## Dashboard Week Day 3 – Using Power BI!

Once again we start our day by presenting our visualisations we made the day before. I was happy to present my radial charts and get a little feedback from Andy about colour and lay out, if you'd like to look over it and give feedback the link is here:...

## A short introduction to Microsoft’s Power BI

Here at the Data school we are habitual Tableau users; hardly a day goes by, including weekends, without opening Tableau at least once, even if only to make a minor tweak or two. I've been here close to 3 months now, and last week ran a brief intro to Tableau training...

## Filter by fields from connected tools in Alteryx macro/app

Today I encountered the following scenario in Alteryx when we were building our first macros and apps. Let's say we want to take the Sample Superstore dataset into our macro and filter by State using a Drop Down Interface tool: The Drop Down Interface tool needs to...

## Dashboard Week Day 3: Foreign Gifts and Contracts Report

It’s dashboard week day 3, which means time for a bit of a change. For day 3, the team must use Power BI to visualize US Department of Education Foreign Gifts and Contracts Report.

## Dashboard Week: #2 Level of NOPD Bodycamera Recordings

The second day of dashboard week began with each of us presenting our visualization from the previous day (here) and explaining the process of how we arrived at the final dashboard. Our present this morning from Andy involved a data source by NOPD (New Orleans Police...

## Dashboard Week – Day 2

For day 2, Andy presented us with very clean data. The data was about police body cam use, in New Orleans. The problem I faced, to begin with, was that I felt that the data was too simple and did not have enough information to create a visualisation with.  So I spent...

## DS 11 Dashboard Week Day 2: I Spy…

Today's assignment was to create a dashboard based on metadata about Body Camera usage in the New Orleans Police Department. The data consists of one entry per recording that was uploaded to the NOPD's archives, with time stamps for when the recording was started, how...

## Dashboard Week Day 2: New Orleans Police Body-Cam Usage

For our second day of Dashboard week we were given the task of visualising the New Orleans police body-cam data set. There was minimal data prep required but the data itself was limited. It only contained when, where and for how long each recording took place (and the...

## DS11 Dashboard Week // Day Two: NOPD Body Wearable Cameras

DS11's dashboard week day two started out well, as the data was relatively clean and could be viewed straight in Tableau. A good deal of my time today was working out what I wanted to say, as well as how. Then it was a 'simple' case of putting it all together in...

## Dashboard Week Day 2 – NOPD Body Camera Data

We start the day off by presenting our dashboard made on Day 1, so amongst some very nice looking dashboards I presented the awful and crude Trump Tower plowing dashboard......