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A look at bar charts and how they can be used to interpret data.

At Qlik, we love data, but data is only useful if it is able to be used. Thankfully Qlik offers a variety of chart solutions so you can visualize your data in the most useful way. Today we start a series focused around charts. We’ll learn what these charts do, and touch on how you can use these charts to best visualize your data.

The first type of chart we’ll be highlighting is the bar chart. Bar charts are a commonly used chart that visualizes amounts as bars. The taller or longer the bar, the larger the amount being represented. Though less common, bar charts can also be used to show negative values across the Y axis of the chart. Two examples of a bar charts can be found below, one displaying a positive value, the other negative.


Now that we know what bar charts do, we can focus on why and what circumstance we should use bar charts to visualize our data. For context, the data we’ll be using is based around sales numbers. These numbers involve sales price, amount sold, the cost of the product and so on. In the example above, our data is based around the master item ‘Margin’. This master item was created by taking the sales price of a product and subtracting the cost of the product to the seller, thus creating a ‘Margin’ or the amount that the seller would make from selling this product after the cost.

Why would we use a bar chart to showcase this data, why not a different type of chart? Below are the same two charts converted into line and pie charts.



As you can see, the reason to use a bar chart for this data instead of a line or pie chart is clarity. The line chart interprets the data as being over a period, connecting the data into one line. Our data is not connected to each other, instead they are individual products. The pie chart again thinks of the data as part of a whole, showing the portion of the whole represented by each item, in the case of the negative product the chart cannot be created as you cannot visualize a negative portion of something. This information would not be useful to the user.

So how can bar charts be used in a real-world scenario? In this instance, the user could want to know what his top five positive margin items are. The user could then use this information to stock more of this product, to push the selling of this product, and ultimately make more money per sell. Likewise, the user may want to see which products are costing him money when sold, thus providing a use case for the negative margins. A negative margin would indicate that the user is losing money every time an item is sold.

Ultimately, bar charts are a great tool to visualize data as individual pieces in relation to one another. The key thought when it comes to bar charts is ‘comparison’, as in, how do these values compare to one another. Hopefully this short blog has begun turning the wheels in your mind with how you can use Qlik and bar charts to visualize your data.

Thank you for giving this blog a read. I would like to make this an ongoing series where we cover different types of charts available at Qlik. If this is something you’d like to see more of, please leave a like on this entry, and comment which chart type you’d like to learn more about.