You accuse the National Health Service (NHS) in England of using “sleight of hand” in the way we are advertising the care.data programme (see go.nature.com/srp5nu), suggesting that we should make it clearer to people that the programme poses potential risks to their privacy and that they can opt out of it (Nature 505, 261; 2014). We believe that this accusation is unwarranted.

“You have a choice” is written in bold on the cover of the leaflet about the programme, which is being sent to every household in the country. The leaflet goes on to say: “If you do not want information that identifies you to be shared outside your GP [general practitioner] practice, please ask the practice to make a note of this in your medical record.”

Last month, we published a detailed assessment of the potential negative and positive impacts of the programme on privacy (see go.nature.com/xcqaql). And, most importantly, patients have the opportunity to discuss the changes with a trained adviser and with their GP.

It would be unethical to introduce this opt-out system without proper publicity, as well as illegal under the UK Data Protection Act 1998. This accounts for the scale of our awareness-raising strategy and our advice last August to all GP practices to start telling people about the proposed changes.