I don’t have copies of a report, for example, if that’s what you mean. I was summarising from my experience.

I’m always open to different research findings, which could be on different audiences in different contexts — or not. Maybe behaviours change.

I would hypothesise though that for accessibility my point would be even more valid. Typically placeholder text in the input field is somewhat greyed out, which makes it harder to read. If it wasn’t it would absolutely look like it’s filled in. To tell people what to do with an input field doesn’t require putting the prompt in the field itself.

Are you able to share your research?