Summary of the Golden rules

The 25 rules at a glance

Before moving into the detailed chapters, I want to give you a compact view of the full structure of the course.

This table is useful as a map: it shows where each rule belongs, what principle it supports, and what kind of mistake it is meant to prevent.

This is the condensed fruit of my work on these rules and guidelines, they could be used as a cheatsheet and a guide you print and put next to your office desk to remind you of what needs to be remembered.

So without further adue, the 25 Golden rules of Data vizulization are:

The 25 Golden Rules of Data Visualization

Principle	Rule	Goal
Completeness	1 - Clear title	The chart must explain itself
	2 - Axis labels	The chart must be interpretable
	3 - Units and scale clarity	Numeric values must be interpretable
	4 - Legend clarity	Series must be identifiable
	5 - Annotation context	Key takeaways should be visible
	6 - Uncertainty cues	Estimates should show uncertainty when relevant
Readability	7 - Readable labels and ticks	The chart must be easy to read
	8 - Color accessibility	Categories must remain distinguishable
	9 - Direct labeling	Readers should avoid unnecessary legend lookup
	10 - Avoid chartjunk	Non-data ink should not distract
	11 - Too many categories	Category charts must remain scannable
	12 - Sort categorical bars	Ordered bars should support comparison
	13 - Scatter overplotting	Dense points should remain interpretable
	14 - Decimal precision	Numbers should be as precise as needed
	15 - Date axis formatting	Time labels should remain legible
	16 - Visual economy	The chart should avoid unnecessary complexity
Integrity	17 - Appropriate scale	The chart must not mislead
	18 - Chart type	The chart must represent data correctly
	19 - Color map quality	Continuous color must not mislead
	20 - Avoid dual axes	Scales should not invite false comparison
	21 - Area baseline	Filled areas should use honest baselines
	22 - Aspect ratio sanity	Shape should not distort comparisons
	23 - Histogram bin quality	Bins should reveal distribution shape
	24 - Category color consistency	Colors should encode groups consistently
	25 - Diverging zero reference	Positive and negative values need a clear zero

How I use this summary

I do not expect readers to memorize this table. I use it as a quick orientation tool. When you are unsure about a chart, this chapter helps you locate the type of problem you may be facing before turning to the detailed explanations in the next chapters.