Self-service BI review: Tableau vs. Qlik Sense vs. Power BI
All three next-gen BI solutions make data discovery and analysis remarkably easy, but Tableau does it best
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When you bring data into Power BI, that data becomes a data set. A data set can be used in multiple reports, and visualizations from the data set can display on multiple dashboards. Similarly, a dashboard (Figure 7) can display visualizations from many reports and many data sets.
Figure 8. Power BI dashboards can display multiple visualization tiles. Asking a question (near the top) can create a new visualization.
A Power BI report created on the website can use data from a single data set; a report created in Power BI Designer (Figure 8) can join multiple data sets. On the other hand, some data sets, such as Power View sheets and SQL views, may look and act like they have already joined multiple tables. A parent-child relationship in the data unlocks one of the coolest features of Power BI, the ability to drill down into segments of the data interactively.
Power BI Designer (Figure 9) allows you to shape and transform your data in ways that the Power BI service can’t. Once you define the shaping steps in the Designer, however, the service can rerun them every time it connects to the data.
In addition to transforming data columns, the Designer can merge tables, drop columns, and create new measures with Data Analysis Expressions (DAX). DAX is very much in the spirit of Excel formulas, only using named columns, not cell ranges. For example:
Previous Quarter Sales = CALCULATE(SUM(Sales[SalesAmount]), PREVIOUSQUARTER(Calendar[DateKey])).
Figure 9. Power BI Designer makes heavy use of contextual menus. Here we are changing the type of a column of data from text to whole numbers. This particular step could also have been done from the Transform ribbon.
In general, you have two ways to create charts in Power BI. You can select variables from a data set, then select a chart type, or you can ask a question in Q&A (natural language query). You can select fields by checking their box, by dragging them into the visualization area, or by dragging them into the correct bucket (axis, size, and so on).
Power BI -- both the service and the Designer -- can currently create some 16 types of charts from your data, although not all of them can be pinned to a dashboard or recognized by Q&A. The visualizations you can pin to a dashboard are bar and column charts (clustered, stacked, and 100 percent stacked), cards (with or without KPIs or images), combo charts, funnel charts, gauge charts, line charts, maps, tree maps, pie charts (with a legend but without details), scatter and bubble charts, stand-alone images, tables or matrixes (with no images or KPIs), and single-number card tiles (made from the question box or a card with a single measure). If you use a card, make sure you have set an aggregation in the Field Well rather than choosing the Do Not Summarize option. (You can view examples of the supported Power BI visualizations here.)
The Power BI app for the iPad (Figure 10) can view dashboards and drill down into reports. It also lets you interact with tiles on your dashboards, create favorites, share dashboards, and annotate and share a snapshot of a tile.
Figure 10. Microsoft Power BI for the iPhone and iPad can view dashboards and drill down into reports. The image shows a sample dashboard for a director of marketing.
From the Power BI site, you can share and unshare dashboards with people in your organization -- that is, people who have the same email domain or occupy the same Power BI tenant. They will have to sign into the service, using either the site or the mobile viewer, to view and interact with the dashboards. A free account is sufficient for viewers.
Colleagues with whom you’ve shared a dashboard can see your dashboard and interact with your reports in Reading View. They can’t create new reports or save changes to existing reports. They do see updates once you save your changes. Colleagues can’t see or download the data set, nor use any of the data refresh operations.
Learning Power BI at a superficial level is a snap, and the introductory learning materials are easy to follow. However, in true Microsoft fashion, parts of the product are obscure, rely on other Microsoft products, and are documented in forbidding complexity.
Analyzing a single Excel table is easy to do and easy to learn, but setting up Power View sheets in Excel and relating them to each other is tricky to do and not easy to learn. Importing data from a remote server may require you to consult your IT department, not only for credentials, but also for the correct driver and settings, as the Microsoft documentation is likely to leave you scratching your head.
How to choose?
Power BI is a promising preview of a self-service business intelligence system. While Microsoft is starting to get the idea that not everyone wants to use Excel for analysis, Power BI currently relies on Excel or the Excel-like Power BI Designer application for data conditioning and joins between data sources. This is acceptable for the price, but not as convenient as Tableau or Qlik Sense.
Similarly, Power BI usually does a reasonable job of setting the axes on visualizations and setting the sizes of bubbles (in bubble charts), but doesn’t let you refine the appearance of the visualization. Again, this is acceptable for the price, but not as convenient as Tableau or Qlik Sense.
Power BI was easier for me to use initially than Qlik Sense, but not as easy as Tableau. When I tried to go deeper with Power BI, however, I kept running into stumbling blocks, obscure documentation, and not-yet-implemented features, consistent with its Preview status.
I like the way that Qlik Sense can connect to essentially any ODBC or OLE DB data source, Excel files, and most delimited text files, although the text data import is not as convenient as Tableau’s. The way Qlik Sense handles Web data sources is pretty good. There are a few common systems of record that Qlik can’t currently reach, but the company is working on that.
I appreciate the automatic indexing of Qlik Sense’s associative, in-memory data set, as well as its facility for handling data too big for memory. I like its way of automatically wiring the visualizations on a sheet, rather than making the analysis define the relationships.
I like Qlik’s associative green-white-gray experience in which colors of displayed values indicate state (selected-selectable-not selectable). This scheme helps you to spot both related and unrelated data without having to dig. I also like Qlik’s way of defining expressions, but not quite as much as I like Tableau’s. Qlik Sense offers good control over the appearance of visualizations -- better than Microsoft Power BI, but not quite as good as Tableau.
I found Qlik's support materials to be very good, but even so Qlik Sense was not as easy as Tableau for me to learn to use; it lags Tableau in both categories.
Qlik Sense is cheaper than Tableau but much more expensive than Power BI. That is consistent with its capabilities being intermediate between Tableau and Power BI. Considering the power and ease you get for the price, Qlik Sense is a good value.
Tableau has an excellent assortment of data sources ranging from Excel, text, and statistical files to database servers, cloud data warehouses, various flavors of Hadoop, and systems of record (such as Salesforce). Importing data is easy, as are data cleaning, inline data transformations, and construction of data joins.
Tableau’s selection of chart types is very good, and it provides excellent control over chart appearance. It also gives the analyst easy ways to display multiple dimensions and measures. Tableau’s maps, dashboards, and stories help the analyst explain the logic leading to a conclusion, and parameterized displays controlled by widgets allow the viewer to play along.
Tableau makes deep statistics available without writing code, although you can do even better if you do write code, especially R code. Overall it’s not hard to learn Tableau at a basic level. Learning the finer points will take some time and patience, however.
Price can also be an issue for Tableau customers. With Microsoft and Qlik offering free options, it can be difficult to justify buying Tableau analysis capabilities for a whole company, although some companies have done so. That leaves the company with a trade-off: Give Tableau to only the people who absolutely need it to stay within budget, or buy a slightly less capable and much less expensive product for everyone.
Finally, note that reporting is an area where some organizations will find Tableau, Qlik Sense, and Power BI to be lacking. These products do a great job of self-service reporting and analysis, but they won’t always meet the needs of IT departments for production line-of-business reports. Some organizations may find they have to buy and maintain a second BI product for these needs, either because they deem the data preparation capabilities of these products inadequate for scheduled automatic reports, or because they want a product that can do more sophisticated statistical analyses on a routine basis, and alert management appropriately when goals or guidelines have not been met.
This story, "Self-service BI review: Tableau vs. Qlik Sense vs. Power BI" was originally published by InfoWorld.
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