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I am in total confusion as to what type of graph to provide the user with for my dashboard. My dashboard deals with user statistic like No. of visits, total points they have earned, etc. But I don't know how to represent the same with graphs and of what kind.

Does each type of graph like bar, pie, area, etc have any significance with respect to data? or is it just a different way to put same data?

In other words, are type of graph and data interrelated?

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    Are you asking us how all types of graphs should be constructed. What exactly is your question here? Can you be specific - such as "Is a Pie chart appropriate for displaying Number of Visits, and if not, what should be used instead"
    – JonW
    Mar 27, 2012 at 10:42
  • The kind that informs without them having to think about it.
    – msanford
    May 24, 2012 at 21:17

5 Answers 5

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Each type of graph or chart has a presentation purpose. You choose chart type depending on what you want to show and what parts of the data that you want to compare.

It is quite easy to just google "how to choose graph type". I found for example this Graphing Tutorial: How to choose which type of graph to use?

I summarize:

Use . . .

  • a Line graph ... to track changes over periods of time...

  • a Pie Chart, or better a Divided Rectangle ... when you are trying to compare parts of a whole.

  • a Bar Graph ... to compare things between different groups

  • a Histogram ... to track changes over time, or probability distributions. Note with histograms, the width is significant, as well as the height, unlike a bar graph

I am sure you will find a lot more about how different graph types can be used, by just googling it.

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  • i had visited the tut, but, i wanted more expertise opinion on the same, whats better place then UX? ;)... tnx for sharing ur time and knowledge..
    – sree
    Mar 27, 2012 at 9:59
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    I see. :) An idea for future questions then is to share your findings so far, when posting. The more precise you can make your question, the easier it will be for the community to give exact answers.
    – JOG
    Mar 27, 2012 at 11:56
  • ll keep in mind next time :)
    – sree
    Mar 27, 2012 at 12:40
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    Statisticians generally advise strongly against pie charts since they distort the subjective assessment of the data with little benefit. In scientific literature, they are almost completely unheard of. However, if the chart only needs to offer an approximate comparison of different sizes then a pie chart may be appropriate, especially since it allows the viewer to put different sizes into relation very quickly. Mar 27, 2012 at 22:30
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    @Konrad, I second the motion against pie charts. There is almost no excuse for them since there's always a better way to represent that kind of information. A divided rectangle is better since people are better at comparing rectangular areas to angles, or a simple bar chart if fraction of whole is less important. If you're using a pie chart, take a moment to find an alternative! May 19, 2012 at 0:08
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Every type of data does have a 'natural' design, but the best is always up for debate. I worked with a expert in data visualisation and he was for example, a strong advocate of never using a pie chart as it is very difficult for users to estimate the difference between the volume of pies.

I find Stephen Few very good on visualisation. He is more practical that Edward Tufte when it comes to electronic display.

Try his dashboard design book. http://www.perceptualedge.com/library.php#IDD

And this is nice beginnings diagram. http://www.labnol.org/software/find-right-chart-type-for-your-data/6523/

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  • tnx for The Answer! :), nice links helps me a lot...
    – sree
    Mar 27, 2012 at 11:20
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If you're interested in choosing a visualisation for a given set or type of data, it seems criminal not to mention Edward Tufte, who literally wrote the book on selecting charts for appropriate display.

I concur with the other answers: which type of chart you use is dependent mostly on how your users need to read the data. Aesthetics of the chart itself are often also very important, which Tufte spends a lot of time talking about in his books.

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    +1. Read Tufte's work. Perfect place to start.
    – DA01
    Mar 28, 2012 at 5:04
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    @kit , thank you for sharing such a valuable link!! :)
    – sree
    Mar 28, 2012 at 9:08
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I do some speaking on this topic in a presentation titled Data Visualization Best Practices for Reports, Dashboards, and Presentations and, when in a pinch I recommend people follow a four step process to choosing a chart:

  1. What's your story? - This is by far the most important step. What is the point you are making to your users? What is the story in the data you're brining out?
  2. Identify types of data in your chart - Categorical or Quantitative?
  3. Identify appropriate preattentive attributes for those data types - Helpful to read Stephen Few's work or viewing my slides referenced above. Or in more detail some academic work like this.
  4. Choose a relationship pattern *- Charts are relationships between fields. Use bar charts for Nominal Comparisons & ranking. Part-to-whole=Convert to percent and use bars to compare the various percentages. Time series=line chart (time on x axis); Deviation=Percent + bars; Correlation=Scatter *
  5. Reduce ink - Remove everything that isn't absolutely necessary to describe the data.
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  • thak you scott.
    – sree
    May 18, 2012 at 5:49
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"Does each type of graph like bar,pie,area etc have any significance with respect to data?"

I would say that a bar, line, area and column graph (I am using the Excel names here) are essentially the same. The difference is mainly in the presenatation.

A pie chart is somewhat different in the sense that it is used when you want to visualize shares or proportions rather than absolute values.

The question is thus not so much about "what users prefer", but what you want to show.

Let's say you want to vizualize how many of your visitors are from Asia, Europe, USA,... You could perfectly use a bar graph to visualize this, but if all regions are present in the data, the bars would sum up to 100%, which is where you could perfectly use a pie instead. If you want to see absolute numbers: use a bar, if you just want to see proportions (e.g. 85% of our visitors are from USA), use a pie chart instead.

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