She told graduating nurses and other health professionals at Brighton Dome: "There will have been times already that have made you uncomfortable when you have seen practice that fell short of your own personal standards.
"You know what you are witnessing is wrong – either technically or morally – and sometimes you will have spoken out and sometimes not.
"I've had those moments too in my career – some of my proudest moments are when I have spoken up against poor practice whatever the consequences for me.
"Maintaining that internal moral compass in the face of opposition is not easy, but I would strongly commend it you as always being worth it. Assuming it's someone else's responsibility to sort it out, make it right, is often a false assumption."
She said there was a continuing need "to be clear about our own personal standards and where we’ll stand up for something against the views of others, however strong."
Dr Redfern received her doctorate in recognition of her major contribution to the NHS and to the education of nurses and other health professions.
She said technology had changed but there was still a need "to recognise how vulnerable people feel when they enter our familiar world – a new and uncertain environment for them tinged with hope that we will treat them well and get it right – and where we have become desensitised to the difference."
There was a need to recognise "the vulnerability of the people who use our services, whether it's for the first time as an acute episode or as 'normal experience' when having a baby or as someone with a long term condition who has become an expert in how to live with it needing the care of the multi–disciplinary team".
Dr Redfern said: "The ultimate tool in continuously improving the patient experience is you, your heart, your hands, your arms, your minds, your compassion and your common sense. Your ability to leave behind the grumpy feeling you had when you left home this morning behind and focus on the person you are caring for.
"One of the most caring and compassionate things we can do is pay clear attention to the other person and listen to them, really listen."