Yes and no

Also called Reliable yes/no, Yes/no response, Consistent yes and no, Establishing yes and no

A reliable yes and a reliable no, agreed and written down, is the foundation of every other choice a person will ever be offered.

What it is

A reliable yes and no means the person has a way of saying each that they can produce on purpose, that means the same thing every time, and that the people around them recognise. It might be a nod and a shake. It might be a look up for yes and a look down for no. Two switches. Two cards. A thumb. A vocalisation for one and silence for the other. It doesn't matter what it is; it matters that it's consistent and that everyone knows it.

Nearly everything else in communication support, from choices through partner-assisted scanning to consent, rests on it. A person without a reliable no can't refuse anything.

Who it can help

People with significant motor difficulties, such as cerebral palsy or locked-in syndrome, where a nod isn't available. People with aphasia, for whom yes and no get mixed up. People with profound and multiple learning disabilities. People in intensive care with a tube in. Anyone whose yes and no are currently being guessed.

For most people the work is on the partner's side: agreeing what counts, writing it down, and stopping the guessing. It's not a stage everyone passes through; some people move straight to a full system. But it's the thing to check first when a person is described as "can't communicate".

How it works

First, find two movements the person can make on purpose, that are different from each other, and that they can make when tired. Speech and language therapists and occupational therapists look for these together, because it's a motor question as much as a language one. Then assign them: this one is yes, that one is no. Then teach it and test it, with questions the person definitely knows the answer to. "Is your name Sam?" "Is it raining in here?" Get twenty in a row right before trusting it for anything that matters.

Second, write it down in the communication passport, with photographs of the yes and the no, and tell everyone.

Third, watch for the traps. Yes-bias: many people say yes to everything, because yes ends the questioning. Ask the same thing two ways. Fatigue: a yes that's reliable at ten in the morning may not be at eight at night. And leading questions: "You're happy here, aren't you?" gets a yes from almost anybody.

Getting started

Watch for a fortnight and write down every way the person seems to say yes or no. Look for the two that are clearest, most repeatable and least effort.

Agree them with the person if you can, and with everyone who supports them. Photograph both and put the photos on the wall.

Ask only questions whose answer you know for a week, and count. When it's reliable, start using it for real, and honour every no. On the Talk board, YES and NO cards can be set up as the first two cards a person touches, with a voice, so a stranger hears the answer.

Where to get help

A speech and language therapist assesses and establishes yes/no; ask for a communication assessment if nobody has. Communication Matters explains it in its AAC guidance. For adults after stroke, the Stroke Association covers yes/no reliability in aphasia. Where a decision hangs on the answer, the Mental Capacity Act requires that all practicable help is given to let the person answer.