But I told them

"But I told them."

Oh, how I would be a rich person if I received even just a penny for the number of times I've heard that sentence. It's usually delivered with a mix of frustration and genuine bewilderment. They sent the email. They said it in the meeting. They mentioned it, clearly, more than once. And yet the work didn't get done, or got done wrong, or the person swears blind they were never told at all. But I told them.

But when we understand the unsettling truth underneath every one of those moments, we get to see the marvellous opportunity hiding there too: telling someone is not the same as communicating with them. Sending is not receiving. You can send a perfectly perfect message perfectly and have it land nowhere at all – and the fact that it left your hands tells you absolutely nothing about whether it arrived in theirs.

We know this, really, and we forget it constantly, because sending feels like progress. You hit send, the little whoosh plays, and you mark another task off your list. Sent. But communication is not complete at the point of sending, far from it. It's complete when meaning has actually arrived in another person's head – and, crucially, when you have some evidence that it did – and, that it was indeed understood. That evidence has a name. It's feedback. Without it, you're not communicating; you're broadcasting and hoping.

The oldest model of communication I've found is an ancient dude who would stand on a hill and share what he knew. His name was Aristotle, you've likely heard of him. His model, fascinating as it is, was a straight line: a speaker discovers something (how lovely is that?), they arrange the message, they clothe the message (think style, rhetorical device) and then they deliver it. One direction, no loop back. Still, I would have loved to hear him speak from the side of a hill.

This model is what a lot of people do today: We mistake saying a thing for landing it.

It helps to see that a message can get stuck at any of several points on its way to actually arriving – and only the last of them counts as communication at all.

It never arrives. The message is sent and simply doesn't get there – lost in a full inbox, buried under the day's noise, filtered, missed. As far as the other person is concerned, you never said a word. (This is the level where noise does its damage, which is a whole piece of its own; here we're interested in everything that happens once a message has arrived.)

It arrives, but goes unopened. It's sitting there, in the inbox or the channel, unread. Delivered is not opened, and a message left unopened has communicated exactly as much as one never sent.

It's opened, but not understood. They read it – and it didn't land. The meaning was unclear, or skimmed, or read through the wrong mood, and what formed in their head simply isn't what you meant, or autocorrect mashed it up so bad it's barely legible. This is the sneaky one, because it looks like success: it was read, so surely it worked. You don't know it did. And those little green ticks on the messaging app....they trick you into thinking you've communicated.

It's understood, and reflected back. The only level that is actually communication. The meaning arrived, and you have proof it arrived – because they did something with it. They acted, asked a return question, argued with it, repeated it back in their own words, sent you the report, did the thing you asked. The message made the full round trip. Until that happens, you are still only guessing.

Which is why feedback isn't a polite optional extra at the end of communicating. It is the communicating – the half that closes the loop and turns a potential transmission into a confirmed one. It's not unheard of for people to take silence as feedback, it might be, but I doubt it. Far more often it means the message is stuck at one of the earlier levels – unseen, unread, or misread – and rotting there gently while you assume all is well. Or, let's face it, you've created turmoil in the other person and they're calming down, and gathering their thoughts and composure, before responding.

A few things follow this, practically speaking. For anything that genuinely matters, choose a channel that hands you the loop in real time – a conversation, a call, a face across a desk – over one that lets you fire and forget. Email is wonderful for the record and hopeless for confirmation and real communication.

I've found it helps to ask for the reflection-back rather than the acknowledgement: "what's your understanding of what we've agreed?" tells you infinitely more than "makes sense?." Watch for action, not politeness is also a good rule of thumb to apply – "got it" is not feedback; the thing actually getting done is. And attempt to close the loop on purpose, because it very rarely closes itself.

A crisp "got it, will do" is feedback. So is a puzzled "what do you actually mean by that?" – the loop reopening, handing you a second chance to be clear before it costs much more. A request for some work that comes back having entirely missed the point is also not uncommon: that too is feedback, telling you quite directly that the message you sent didn't land – and telling you now, rather than three weeks on when it's far more expensive to hear. That same principle is the same one that generates zero laughs to what you thought was a good joke during a presentation too.

The knack is to treat all of it as information rather than irritation, because every one of those is the loop doing its job.

This is really the natural companion to the problem of noise, and the two are best read as a pair – the two halves of the same loop. Noise is everything that stops a message arriving. Feedback is how you find out whether it did. Ignore the first and your messages get mangled on the way; ignore the second and you never even discover that they were.

We can't avoid all of this – we still have to send. But sending is the beginning of the job, not the end of it, however much the whoosh would like to convince us otherwise. So the next time you catch yourself reaching for "but I told them," it's worth pausing on the remarkably insightful question: did I tell them, or did I actually land it – and how, exactly, would I know?

Because sent, it turns out, is not the same as received.