Bar Graphs and Presentations

One of the hallmarks of a good presentation is the bar graph. Bar graphs are often used because they provide a quick understanding of how one variable compares to another, and they can be highly effective during marketing promotions or even used in an informational statistics lesson. However, just how do these graphs actually work? And once you've created them, where do you go from there? This blog post provides an explanation for everything.

The world has never been more data-driven than it is right now. Whether that's through the spreadsheets and desktops we're using each day or on mobile devices like tablets and smartphones, digital information is everywhere. The number of businesses that use data in some way or another is also rising. Some businesses, especially in the financial and software fields, involve huge piles of data.

The need to effectively display that data and make it easily digestible (to the point where others can understand it) is an important element of business administration. How do you turn large amounts of data into a format that everyone can understand? That's where the bar graph title comes into play. Here's why:

The Very Basics: Definitions & Purpose

A bar graph, as its name states, is a graph made up of bars. These bars represent either numbers or categories of numbers being measured by certain attributes like weight or price (or even alphabetical listings). There are two main types of graphs: line and bar.

A line graph shows the relationship between multiple variables. In a line graph, the x-axis refers to time, and the y-axis refers to value or measurement within that time frame. An example of this type of graph would be showing the incomes of various countries in terms of GDP per capita or population. A line graph is a useful tool for showing trends over a long period.

A bar graph shows how independent variables relate to one another. Bar graphs are usually much shorter than their counterparts and show how things change over time in discrete values or categories. For example, a bar graph that presents the results of a survey on favorite flavors of ice cream would group the results in categories such as brand or color (and even how many people voted).

What Are Bar Graphs Used For?

Bar graphs are simply another form of visual data. They're everywhere, including on websites and in print publications. They can be used in any situation where there is need to visually display information. These may include situations such as:

– Businesses displaying sales or market share rates over a period of time.

– A list ranking diet plans by popularity on an internet site that sells these diet plans. 

– A chart showing test scores over three consecutive years for each student in a class. (This would be a good opportunity to work in a line graph, as well.)

– A chart on this blog of how many subscribers have been added each month since January 2013 (as a way to increase my own traffic).

An Example of How Not to Do it. The following graph came from a U.S. government website that often has data concerning business and labor statistics:

A blog contributor conducted a simple experiment, which James Clear so nicely explains here , on how easy it is to present the same data in different ways. His first example was the U.S. Bureau of Labor Statistics report on employment status among veterans and nonveterans. They presented the data in a bar graph, as you can see above. This is not a terrible graph, but by making it into bars, the same data can be much more easily understood by most. His second example shows how different presentations of the same information can drastically change the way we see it.

Here's another example: The Atlantic made a bar graph about gun control for an article published in 2013.

The article itself was about gun control statistics and legislation that had been passed earlier that year. The accompanying graphic was used to show how frequently certain things had happened between January 2001 and December 2012 (the dates when this data was recorded). It's a good example of how the same data can be seen in different ways, depending on how it's presented.

Our Take on Bar Graphs and How to Create Them

So, how do you really create bar graphs? And once you've got them going, what do you do with them? Fortunately, the process is actually quite simple. Just follow these three steps:

Choosing Your Data

The most important element of any bar graph is the data itself. This data will make up your bars and will tell your story. The most effective bar graphs use real data that are gathered from reputable sources (more on that later). If you are creating a bar graph on your own, it's best to pick numbers that have some kind of meaning behind them. If you're creating a graphic for your major in college, then consider using data regarding the number of students who graduated with a major in that particular field. If you're doing a graphic for work using company sales figures, then consider using sales within certain regions or particular products (or even overall sales results). Use whatever information works best for your own situation.

Formulating the Bars

The next thing to do is choose how many bars to use and how they should look. The most common use for bar graphs is listing numeric data. For example, you might use a bar graph to compare the number of sales people (say) to the number of sales they made in a given time frame. Use whatever works best for your situation and the data you have available.

Take a look at this example:

This simple chart shows state population growth between 1980 and 1990. It's not too complicated, but it does show how bars can be used to represent numeric data in a very pretty way!  This is how I did it: 

Step 1: I chose one primary category from data that I had collected, which was state population growth. Step 2: The next step is selecting what units of measure will be used in my final graph. I don't just want to use the raw number of people in each state as my bar, since that would be too cluttered and hard to read. So, I'm going to look at percentage growth instead. Step 3: I decided to use bars that start with New York and end with Wyoming (since Colorado has the highest percentage growth). I also decided to shade each bar to make the graph even easier for readers to understand. Step 4: Finally, I added a title and subtitle for my graph so it would be as easy as possible for readers to understand what was going on.

Step 4 is probably the most important step when it comes making good bar graphs .

Conclusion

This article shows that, while it's very simple to create great graphs, there are many factors that play into what makes a graph "good" or "bad". In the end, though, the best way to learn how to create good graphs is simply to practice and experiment.

You'll probably find that you need different amounts of bars for different situations. You may also find you need to size your bars differently than what is described above.

Remember: your goal should be clear from the beginning. And make sure you always use data that makes sense for your project (so you won't have any strange results).