by Daisy Jones

Over the past couple months, I have been devoting a lot of time to learning about Power BI. I am still very much a fan of Tableau, however learning a new skill is always welcome. This blog is to present my initial thoughts on Power BI and its functionalities. 

The Interface in Power BI

When using Power BI for the first time, the interface can look a little daunting. It takes time to get familiar with where your items are. Below is a quick comparison of the tools. It’s worth noting that these tools, though they may have the same or a similar name or function, are not identical. Features such as  ‘Show Me’ differ. In Tableau you can use the ‘Show Me’ feature to help you build your charts, but really you’re using the rows and columns. In Power BI, you have to use the ‘Show Me’ to build your charts.

1. Canvas. This is where you can bring in your charts and create your Reports. 
2. Show Me. Very similar to the show me tab in Tableau, the only difference is these are the charts you are able to build. You have the choice to import visuals, but the selection is quite limited. 
3. Fields Pane. You can find your tables and fields to create your visuals. 
4. Report Tab. These are the tabs for all the reports you build. Notice that there isn’t a selection for a Dashboard. That’s because Dashboards are shown in the Power BI Service, not Desktop. 
5. Data Source. Here is where you can view the tables of your data and see the relationship model of your tables. 

One of the things that is striking for me as a Tableau user is how there isn’t an instant distinction between reports and dashboards. This is because in Power BI Desktop, you build the reports and then you pick the charts from the report to ‘pin’ them on a Dashboard in the Power BI Service (= Tableau Server). 

The distinction between both of these is how they are used by the user. A Dashboard is to be used to show KPIs and up to date information that gives answers to business questions. A Report is to allow the user to investigate their data which then can be placed on a Dashboard. 

At the moment, using Dashboards in Power BI doesn’t seem to have many benefits, but this is coming from someone who enjoys adding as much interactivity to dashboards as possible. 

Relationship Model and Power Query

This is where I was quite impressed with Power BI. As much as I love the Tableau Data Model with the Relationship noodle, I find that it was hard to understand or see what was happening with my data and how I connected the Tables together. 

Power BI makes this easy by showing a diagram of your tables connected. You can see the direction of the relationship and what kind, if it is a many to many, one to many etc. You also have the flexibility to change accordingly, making sure that you are not losing any data. 

Alongside the Relationship model, the Power Query editor is a dream come true for users as it is like Excel and Tableau Prep collided to create an editor to help clean your data. You can transform and manage nulls in your data, while keeping track of the applied steps as you go. This was particularly useful as this is placed in one tool, so no need to have multiple tabs open to edit your data. 

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Chart Building 

In terms of building charts and visuals, Power BI definitely makes this a very simple task. Just select the chart type you want and viola, you have your chart. In Tableau there are certain charts that require you to add a little more effort than a standard bar or line chart, so it is nice to have the work halved in Power BI. But that is where the benefits end. 

I very much enjoy the flexibility of being able to create any charts. Yes they may take many tutorials and an abundance of calculations, but the satisfaction of building a circular bar chart is immense. So to be limited to a handful of charts can be frustrating, especially when there is a particular business question that cannot be answered by a bar chart. 

Formatting

I am a big fan of formatting. I would be happy to sit down with a cup of tea and spend an afternoon formatting. However doing this in Power BI was very difficult as a Tableau user. 

To start, it is very difficult to find where to format certain parts of a chart. I know that I have to select the paint brush, but from that point, it can be difficult to work out where to go. 

Colour to me is an integral part of a visualisation, it can highlight key points in your data, it can show the meaning of the visual and add depth. However, some of the colour choices are limited.

For example, While building a profit analysis dashboard, if I wanted to show profit over time with a line chart, but also add colour to highlight when profits were below zero, I could bring in colour in Tableau. If we try to do a similar thing in Power BI, we can only select one colour to represent the whole line. This is not the end of the world, but it can be disappointing if you have a particular view or scheme for your report. It can also be hard to then define the line when it becomes a positive or negative value, unless you use a reference line at zero or a clear axis. My recommendation is to use an area chart as that will fill in the base of the line which is clear to see if it is negative or positive. 

Conclusion

So have I been swayed over to the Power BI side? No. But I can definitely see the appeal of it. It has a simplicity in terms of building reports and the familiarity of Excel can make Power BI seem like the holy grail for Data Analytics. However, if you are starting from a Tableau background, the cracks are easy to spot, especially when you use Tableau on a regular basis.