Noah Iliinsky
Visualization & interaction designer. Feminist. Practical cyclist. Author of vis books: http://www.oreillynet.com/pub/au/4419
My tweets: my opinions.
Numerical data is read right-to-left; that is, we compare numbers by first looking at their ones digit, then their tens, then their hundreds, and so on. This is also how most people learn arithmetic — start on the right and move left, carrying digits as you go[1]. Therefore, tables should keep numerical data right-aligned.
Design Better Data Tables
Matthew Ström
1.3K50
The right to left reading may or may not be true. However, right aligning numbers has one other very important feature; it makes comparision of different orders of magnitude MUCH easer. Consider:
89
6789
456789
When the numbers are left aligned, we’re now looking at digits which are all different orders of magnitude in columns. If we right align them, the ones, tens, hundreds, etc., are all aligned in consistent columns.
This also makes scanning for the largest values easier, in that you can look for the relatively longer strings (also possible with left-aligned), and the “extra” protruding digits are the notable significant figures.
