A study on university students has found that a new herbal drink named Somnila is highly effective at improving sleep quality.
Explain one limitation of asking students to self-report the effectiveness of Somnila.
Practise AQA A Level Psychology Self-report techniques with exam-style questions for A Level Psychology. 40 questions, matched to the AQA A Level Psychology (7182) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.