I’ve Downloaded Power BI, Now What? | by Alissa Owen

I remember the day I was first introduced to Power BI. It was a warm summer afternoon in 2019 and I looked at my colleague’s dashboard in awe. I asked her how I could create my own data tapestry and she told me Power BI was easy, like learning to ride a bike. And she wasn’t wrong; learning Power BI for me was like learning to ride a bike….except the bike was on fire, I was on fire, and everything was on fire because I was in hell. 

I made the process needlessly hard for myself because I was trying to run before I could walk. Now in my role as a data literacy/ Data & Insights for Business Decisions coach, I often see apprentices making the same mistake I did in neglecting the foundations. The ultimate goal of anyone using Power BI is to create great visualisations that give way to accurate and meaningful analysis. To ensure we can trust our output, we need to begin by checking the data that we are inputting. 

Here are my top tips to get started with Power BI, and catalyse your journey from novice to wizardry. 

Loading vs Transforming

Once we click “get data” and choose what we want to import into Power BI (in my example here, it’s an Excel sheet - other formats are available), we will see in the bottom right-hand corner, a choice to either (i) load or (ii) transform my data. But what does this mean and how do we know which of these options to choose?
If we choose “load”, it means we are happy that the data set is sufficiently cleaned and we wish to move on to visualising our data. However, the “transform data” option allows us to view and make changes to our data before it’s loaded which will ensure our visualisations turn out as we want them to. 

TOP TIP: It is best practice to go with “transform data” to check there isn’t anything that needs to be changed, even if we are confident that our data set is clean.

Now you know why we transform data, I am now going to take you through some common stumbling blocks that apprentices have, and how to overcome them. 

The Correct Column Names are in the First Row

This is a common issue and easily fixed. Like in the example above, the column headers are, unhelpfully, ‘column1’, ‘column2’, and so forth. This will be unclear when we begin to visualise the data. The more eagle-eyed among you will have noticed that the ACTUAL names of the columns are in the first row, therefore we want to promote this row to be our headers. To do this, in the ribbon at the top, select “Transform”,  and then “Use First Row as Headers” 

Checking Data Formats 

There are five data types in Power Query but the most common three you will work with are 

• Numerical
• Date/Time
• Text

Power Query will automatically detect the data type by default, however, it can get it wrong which will impact your analysis. Therefore it is best practice to check that each column is in the correct data format. The icon to the left of the column header tells you which format that column is in. E.g. The ‘ABC’ means it is in text format, and the calendar icon means it is in date format. If you want to change the format, you can do this by left-clicking on the icon, which then gives you the list of formats. Then select the format you want to change it to.

How to Undo a Change 

Down the right-hand side of the page, under ‘APPLIED STEPS’, you can see all the steps you have made to transform your data.

If you want to undo any of these, click the “X” next to the step you want to undo.

Moving onto Visualisations

When you are happy that you have made all the data transformations you want to, don’t forget to click “close and apply”!

The above is by no means an exhaustive list of everything you can do in power query, so I’d implore you to continue researching what else you can to improve your data quality. To get you started, I'd recommend Excel campus on YouTube.

Just as “the journey of a thousand miles begins with a single step”, an awesome Power BI dashboard starts with high-quality data transformation. If you can master quality assuring your data sets, you’ll be able to gain insights from your visualisations that you can trust. 

Alissa Owen is a Data Literacy/ Data & Insights for Business Decisions Coach at Multiverse.