Designing systems that communicate information, like train services, government websites, or graphs, is hard! Part of the reason it’s hard is because no two people process information in exactly the same way. Human beings are wondrously, irritatingly, insanely, varied and complex. It’s very likely that even a system tailored precisely to one specific person’s needs and preferences would fail that person on days when they were ill, upset, or just had a lot going on.
This is why important information should always be presented in multiple different ways by using different channels of information. Channels of information in a graph can be things like colour, shape, size, texture, or spatial position. In a wider context they can include text, sound, pictures, tactile forms (such as Braille, and tactile paths), or video, among other things.
In real life, channels of information can vary hugely. When you meet someone at a conference, you introduce yourself verbally, but you also have a name tag on, and maybe even your name, affiliation, and profile picture in the conference app – that’s three channels of information for the same details! A podcast can be a video on Youtube, audio only on a podcast app, and available as a text transcript. The goal is to make accessing and recalling the information easier for everyone, by including it in different ways and different places.
Take trains, for example. Melbourne has a shiny new train system we are creatively calling “the Metro”. In reality it’s not really a new system, it’s a new segment of line with a handful of new stations that connect an existing south eastern line with a northern one, but it’s the most excitement our public transport system has seen in a long time.
The first time I rode the Metro, in January 2026, I was headed with some friends to Footscray for brunch. I parked at Huntingdale Station, and the ride in was fine, except that we had to skip one station – the State Library – because of a fire alarm.
On the way back, the State Library was still greyed out on the system map shown in the train – a nifty way of communicating that we would not stop there. I thought it was handy that the system map displayed on the train showed – in real time – where the train was on the line. As someone with ADHD who is easily distracted by a book or conversations in group chats, I have a tendency to look up with a start and panic that I have missed my station (I have an embarrassing level of track record in this department).
The friends I was travelling with got off at Town Hall, and when the audio announced that we were at Anzac station, I looked up and saw that the map showed that we were still on the way there. I assumed the map was wrong. After all, we were at a station, not in between. Two separate announcements – the text on the screen and the audio announcement – said we were at Anzac station. I took a photo of the map, and as the train pulled out of Anzac station, I texted the family chat about it, chuckling about the vagaries of IT systems. By the time I put the phone down we were pulling into … Anzac station???
I was utterly bewildered. Had I completely misunderstood the last ten minutes of the trip? What the heck was going on here?
It was only when I met up with my friends again later in the day that I discovered that the train had, in fact, stopped at State Library Station, but because the system still thought State Library Station was inactive, the automated signs and announcements said it was Town Hall. So my friends got off at State Library, thinking they were getting off at Town Hall, and I was left on the train to become horribly confused about where I actually was.
How, you might ask, did my friends not notice that they were getting off at the wrong station? This is how.
Notice how you can get off the train using this door and not see a single sign bearing the station name?
And it gets worse. This is the view from the train door at a different station.
A deliberate decision has clearly been made to make both stations look exactly the same. Same raw concrete. Same orange accents. Same floor tiles. Now, colouring the stations differently would probably not have helped my friends, who were visiting from Sydney. But it would have been an extra channel of information for regular commuters caught up in the same confusion. Also, there should just be more signs. Trains, by nature, are full of people standing and getting in the way of your view. It should be difficult, if not impossible, to look out of a window or a door and not see a station name. (Name signs are also distressingly infrequent on the other side of the train, along the wall of the tunnel, so that’s no help!)
Sometimes you can see the name from the door, but sometimes you can’t.
That’s not good enough to prevent confusion.
Train stations are a classic case where the channels of information could and should be many and varied. If each station had a unique and recognisable design (you could make the State Library book themed, how fun!), then it would help identify the issue when you look up, confused, or the system is reporting a station you are not, in fact, at! (This, of course, should never happen, and the IT system should have been robust enough to identify that it had stopped at the “out of service” station, but that’s a whole other rant.)
You can’t just use colour, because it won’t work for colourblind folks. You can’t just use text based signs, because it won’t work for vision impaired folks, or those who can’t read. You can’t just use sound, because it won’t work for deaf folks. It’s a funny thing, but using multiple channels of information for folks with particular accessibility needs also helps everyone else, because it gives them more signals that their brain can decode in the background, even if they’re not paying perfect attention (because who, in this age of devices, is ever paying perfect attention??).
Multiple channels of information are also important in data visualisations. If there is one particular data story you want your readers to take away from your graph or other visualisation, highlight it by picking it out using multiple channels of information – such as shape AND colour, or size AND position – and it will help you communicate better, and with more people.
Back when I used to teach large classes, I quickly learned that students wouldn’t respond to an email. They needed a second, sometimes even a third, to prompt them to respond. Staff were the same! And it’s the same with information. Anytime you have important information you want everyone to see and understand, the more often you present it, and the more different ways, the better.