A few of the million+ decisions your software program can’t make for you:

10. Which chart is best for your data. Yes, I’m well aware of Excel’s Suggested Charts feature. No, don’t even think about it. There’s no substitute for your critical thinking skills.

9. How much ink is necessary. Will your viewers benefit from light gray grid lines, or should you remove them altogether? Ask 10 different people and you’ll get 10 different opinions. You’ll have to think yourself outta this one.

8. How many decimal places are needed. One argument is that decimal places add precision – if you’ve got decimal places, why not display them? Another argument is that our datasets are rarely complete enough, cleaned enough, or generally accurate enough to warrant giving the viewers lots of decimal places (and therefore, a false sense of precision).

7. Whether you’re going to stick with a default color scheme (please, NO) or customize your color palette to match your client’s brand identity.

(And who chose Excel 2013’s color palettes, anyway? Lime green, royal blue, and orange? But that’s an article for another day.)

6. The extent to which you’ll label your data. Do your viewers need to see every point on the line, or just the beginning and end points? Or just the highest line? Or just the lowest line?

5. Whether your chart needs to be rotated to avoid diagonal text. In this scenario the answer is yes! rotate that chart! but your software program won’t automatically do this for you. You’ll have to determine whether your data labels need some additional space, and if so, swap your vertical bar chart for a horizontal bar chart.

4. Whether your viewers need aggregated or disaggregated data. It doesn’t matter how much you paid for your software program. Your computer doesn’t know whether your viewers would benefit from a single visual that contains aggregated information or whether your viewers need to make comparisons across four different variables simultaneously through a small multiples layout. But yes! Your brain! It knows!

3. Whether your viewers will really understand that diverging stacked bar chart, or whether you should just stick to a regular old stacked bar chart.

2. Which patterns to emphasize and which patterns to hide, like whether viewers need to see all the peaks and valleys (line) or whether you need them to focus on just two points in time (slope).

1. And in case it isn’t obvious yet, your audience is pretty darn important. Your software program will never understand your audience’s numeracy level, data visualization level, interests, time limitations, or information needs as well as you.

Ready to dive in and start training your brain to think through these considerations and more? In 48 hours I’m co-leading a public data visualization workshop with THE Stephanie Evergreen in Washington, DC. Upcoming speaking engagements are listed on my calendar.

Want access to the files used in this article? Sign up for my newsletter and I’ll send ‘em your way.

Here are some simple strategies for communicating clearly with chart color.

Strategy 1: Select a custom color palette.

Rather than using Excel’s default colors, match your chart to the organization’s logo. (Consultants: Match your client’s logo, not your own.) For my grad school projects, I align everything with my university’s logo.

Does the organization have a super basic color scheme? My grad school’s logo is green and yellow, which doesn’t give me many options to work with. So, I found a similar color palette on design-seeds.com. I used the instant eyedropper to find each color’s RGB code. Now I’ve got six colors to play with instead of just two.

Strategy 2: Figure out if your categories are nominal, sequential, or diverging.

Nominal or categorical variables are things like race/ethnicity (African American, Asian, Latino, White, etc.) or gender (male or female). Think about which pattern you want to emphasize, and use darker action colors to draw attention to that finding.

Sequential or ordinal categories have a natural order, like age ranges (5-9 year olds, 10-14 year olds, and 15-19 year olds) or years (Year 1, Year 2, and Year 3 of an evaluation). Sometimes categories go from less to more or from nothing to something. An example of a nothing to something progression is a satisfaction survey question that asks program participants to assess how likely they are to recommend the program to a friend (not at all likely, somewhat likely, very likely). For these charts, the action color can represent the something and white can represent the nothing:

Divergent categories are opposites, like agree/disagree scales on surveys. An example is a similar satisfaction survey question that asks participants to indicate whether they agree or disagree with the statement “I’d recommend this program to a friend.” When charting divergent variables, you might design a diverging stacked bar chart, as shown below. Select two different colors from your palette, like greens for agreement and yellows for disagreement. The extreme values (strongly agree and strongly disagree) get the darker colors.

(For a deeper discussion of these principles, check out colorbrewer2.org.)

Strategy 3: De-clutter by increasing white space and switching some black text to gray.

Which information is most and least important? Let’s de-clutter by removing or reducing anything without a crucial purpose. We want the reader’s attention focused on our most important patterns.

For example, if you’re using Excel, you might improve upon the default settings by deleting the border, the grid lines, or the tick marks. If you decide to keep the grid lines or tick marks, try adjusting them from black to gray so they fade into the background. You can also remove the legend and put labels within the chart itself (like that first bar chart with race/ethnicity information). Finally, you can outline shapes in white to give the chart a crisper look and feel (like the diverging stacked bar chart shown above).

Do you have additional color tricks to share? Please share your comments below.

Want to create one of these charts? Download my Excel file. Or, want a step-by-step tutorial? Stay tuned: Next week’s dataviz challenge is a diverging stacked bar chart!