Charts that Suck

Yes, I know every excel blog has a feature like this, but I'm not feeling inspired today and I need some filler.  Also this chart just plain irritated me.

Problems I have with this chart:

1. It's 3d.
2. The bars are all different colors.
3. It's using the default Excel palette.  Not only is everyone bored with it by now, it was ugly to begin with.
4. It's 3d.
5. The key is an inefficient way to label this type of chart.
6. I don't think these are "relative prices".  Just prices would be fine.
7. The bars are touching!  Data needs to breathe.
8. Vertical text.
9. It's 3d.
10. The "Liquids" label on the axis wouldn't be necessary if the chart was labeled correctly in the first place.
    

Things that I appreciate about this chart:

1. The data is ordered in a useful way.
2. A bar chart is the correct graph for the data, as opposed to a line graph, scatter plot, or pie chart.
   
3. No wacky textures or other irritating effects were added.
   

Let's fix it.  First of all, change the color palette.  I could write a book about proper color palette use in Excel.  It wouldn't be terribly informative or correct, and I'd probably end up anthropomorphizing the colors and turning it into trashy cyberpunk pulp starring the color fuschia, but I could write it.  I'll put a post together about it in the distant future.  For now, here are the rules for a good color palette (I'm not intentionally making this post a series of numbered lists, it's just kind of turning out that way):

1. White.
2. Black.
3. 5-10 shades of gray, ranging from very light to very dark.
4. A strong red, something a little deeper than just the 255 red (for "bad" or negative numbers).
5. Several monochromatic color series for ordered data.  Generally, lighter is better because you can use it for backgrounds as well.  I like blues and greens for this.
   
6. A series of complementary colors for unrelated data.  Think pie chart.  I like autumn colors or colors that remind me of food for this.

Here is my current color palette.  You can see that I've broken some of my own rules, but this is a work in progress.  I'm not happy with the red series and I need more gray.

Because this is a chart about money I'm going to use a green*.  That's probably more thought than you need to put into something like this, but anything worth doing is worth doing right.  I'm just getting into all of the psychology behind color, and I'd recommend Pantone Guide to Communicating with Color as a good place to start.

The background of the chart should be very light gray or white, grid lines and borders should be gray if you want them, the actual bars should not have borders.

As far as the fonts, I like Georgia for text, Tahoma for numbers.  You might have heard that you should change the font based on whether it will be read on paper or electronically as Serifs are supposed to be easier to read in print and Sans Serifs are supposed to be easier to read on a computer screen.  This is hogwash and hasn't been supported by scientific study; Google it if you want.  Regardless of medium, Georgia is a damn fine font, though the descending numbers make it unsuitable for numbers by themselves so that is why I also use Tahoma.  I usually use 8 point font for labels, 10 point font for titles, but the scale really depends on where you're going to put it.  As a rule though, titles should be about 2 points bigger than the rest of the text for most applications.

I changed the chart to a horizontal bar chart so that the long category names would fit easily and we wouldn't have to use a key.  The bars are also a little too skinny by default.  The chart reflects the data, so if you want your data to look solid you'd better use bars that don't look like they'd snap off in a stiff breeze.  I changed the gap width to 70.

The repaired chart:

Note to self: stop leaving the mouse cursor in screen shots.  That's all for today.  In unrelated news, my girlfriend is going to buy me office 2010 for Christmas.  I'm a little scared to leave the comfort of 2003 behind, but it will be nice to have my own Excel license if I ever want to start freelancing.  Next Christmas I want Tableau.

-David
  
* I realize that not all money is green and that not all of my readers are from the United States, but U.S. currency is the most recognized currency in the world according to an unscientific poll I conducted that technically has the largest sampling bias possible.