The Art of Seeing Data
Imagine a giant spreadsheet with thousands of rows of sales numbers from the past year. Could you spot the best-selling month, or a sudden drop in sales, just by staring at the raw numbers? It would be incredibly difficult.
Now imagine that same data as a simple bar chart. You could instantly see the patterns, the peaks and the trends. That is the power of Data Visualization.
1What is Data Visualization?
Notice what that definition is really claiming: the data does not change at all. The numbers in a chart are exactly the numbers in the spreadsheet. What changes is how much work your brain has to do to understand them.
2Don't take our word for it
Below is half a year of sales figures, shown two ways. Find the best-selling month in the raw numbers — actually try it, and notice yourself reading every single value. Then switch to the chart.
Same numbers, two different formats. Click the month you think sold the most — first as raw numbers, then as a chart.
Same six numbers. In the table you had to read all of them and hold a running maximum in your head. In the chart, the answer arrived before you had finished looking. And notice: with a whole year of data, or ten years, reading gets steadily harder while looking stays instant. That gap — between reading data and seeing it — is the entire reason this chapter exists.
The Map and the Directions
3Why our brains prefer pictures
Reading numbers is a sequential task — one value after another, each one held in memory while you compare it to the next. Seeing a shape is a parallel task; your visual system takes in the whole picture at once. A chart converts a slow job into an instant one:
- Patterns — Is this going up, down, or wobbling?
- Peaks — Where is the highest point? The lowest?
- Trends — Where is this heading if it carries on?
- Outliers — Which value does not belong with the rest?
What does data visualization actually change about your data?
Which of these is a job a chart does better than a table?