This is the second of 10 posts where I’m listing tips for better charts. Please take a look at the first post where the project is discussed. These are my chart formatting tips:

  1. Use the right chart type for the data and the problem;
  2. Apply sound design principles;
  3. Use color strategically: mute axis and grid lines by graying them out; gray out some contextual data also; use soft colors; use saturated colors sparingly and with a clear purpose of emphasis;
  4. What the users see is not what you see in your monitor: if needed, test for other monitors and output formats (b&w print, color print, PDF, overhead projector);
  5. There is no rational justification to use pseudo-3D charts and other dubious effects (gradients, glow…), so never use them if you what to be rational;
  6. Use a clear font;
  7. Don’t emphasize everything (for obvious reasons);
  8. The y axis scale should start at zero; this is particularly important if you are using bar charts; make sure you have a good reason to break this rule;
  9. A chart is not a table: by labeling every single data point you make it harder for the user to search for trends or patterns; if you have to, place the labels where they can do no harm;
  10. Annotate: Add labels for the last, the lowest, the highest or any other relevant data point; add data or comments where appropriate;
  11. Bonus tips: Use smaller charts and never accept the Excel defaults;

What are your best chart formatting tips? Please share them in the comments!