Legend match
A line chart with a legend asks the reader to do a small memory task: look at a line, find its colour in the legend, read the name, look back at the line, and repeat for every line. With four series that is a lot of back and forth, and on a projector, where colours shift and the legend is far away, it is often where the audience gives up.
This game makes that effort visible by removing the legend entirely. Each chart has four unlabelled lines in distinct colours, and a list of names with a clue about how each one behaved: peaked in a given year, stayed flat and then doubled, fell every year. Match each name to its line by reading the shapes. Pick a name and click its line, or use the colour list next to each name.
After you check your answers, the chart switches to the version it should have had from the start, with each name written at the end of its line in the line's own colour. Notice how much faster the second version reads. That speed difference is the reason most data journalists and chart style guides prefer direct labels whenever there is room for them.
Four charts, no legend
Four lines, no legend. Read the clues and work out which line is which. Pick a name, then click its line, or choose a colour from the list next to each name. Check your answers to see the labelled chart.
Round 1 of 4
- Atlas Peaked in 2016, then fell every year The orange line.
- Beacon Flat until 2019, then doubled The purple line.
- Cobalt Climbed steadily every single year The pink line.
- Delta Dropped sharply in 2020, then recovered The teal line.
Matching colours to a legend sends the eye back and forth once per line. Write each name at the end of its line and the legend becomes unnecessary.
Round 2 of 4
- Search The highest line all year The teal line.
- Social Spiked in July, then fell back The pink line.
- Email Slumped over the summer, recovered in autumn The purple line.
- Referral Slid slowly downwards all year The orange line.
Matching colours to a legend sends the eye back and forth once per line. Write each name at the end of its line and the legend becomes unnecessary.
Round 3 of 4
- Coffee Roughly doubled from 2020 to 2025 The pink line.
- Cocoa Flat for a decade, then tripled in two years The orange line.
- Sugar The lowest line throughout The teal line.
- Tea Rose until 2018, then stayed flat The purple line.
Matching colours to a legend sends the eye back and forth once per line. Write each name at the end of its line and the legend becomes unnecessary.
Round 4 of 4
- Smartphone Overtook every other device in 2014 The purple line.
- Laptop Barely changed over the whole period The orange line.
- Desktop Started highest, then fell every year The teal line.
- Tablet Rose fast until 2015, then levelled off The pink line.
Matching colours to a legend sends the eye back and forth once per line. Write each name at the end of its line and the legend becomes unnecessary.
Questions
Why label lines directly instead of using a legend?
A legend box makes the reader look back and forth between the key and the lines and hold the colours in memory while doing it. A label at the end of each line removes that round trip, and it also helps readers who have trouble telling some colours apart.
How many lines can one line chart carry?
Four or five lines stay readable when they do not cross too often. Beyond that, two approaches work better: highlight the one line the chart is about and grey out the rest, or split the data into small multiples, one small chart per series on a shared scale.
What if the colours are hard to tell apart?
Red-green colour vision deficiency is common, especially among men, so colour should never be the only way to identify a series. Direct labels, different line styles or markers, and a palette that also differs in lightness all keep the chart readable when hue alone fails.
Is a legend ever the better choice?
Yes. When several small charts share the same series, one legend can serve all of them, and a map coloured on a scale needs a key to translate colour into values. The problem is a legend that sits in a corner of a single chart where direct labels would fit.