If you want to learn about someone, should you ask them? Two bits of research published recently cast doubt on the validity of self-report as a tool in psychology and psychiatry. The first found that teens who reported that they suffered from bullying experienced more mild 'psychotic-like' symptoms. That correlation would be consistent with the idea that these symptoms arise as a response to stress. However - the same study found that there was absolutely no correlation between peer ratings of whether someone was bullied, and their psychotic symptoms. Only self-report was associated.
The second study looked at whether a crisis intervention program - intensive mental health care - helped people who'd recently attempted suicide. The results showed that, compared to a control condition, suicidal patients who got crisis care self-reported fewer subsequent suicide attempts. But a trawl of hospital records painted exactly the opposite picture - the intervention group were more likely to end up in hospital with a second attempt. Remarkably few studies in psychology and psychiatry compare self-report to other measures of behaviour. This is because self-report is typically a lot easier. If these papers are anything to go by, however, this is a serious limitation. Self-report can be radically at odds with other measures of behaviour. Which raises the question - who's right? Are the self-reports right, when they clash with other sources? I don't think there's an easy answer. In the bullying case, it might be that self-report is more accurate, because the peers doing the peer-report are the bullies. In the suicide study, maybe the self-report was more accurate, because the patients knew about attempts that never made it to hospital. But on the other hand you could argue exactly the opposite. Maybe the self-reports of bullying just reflected whether the kids thought their classmates liked them. Maybe the patients were ashamed to admit that they'd reattempted suicide even though they'd got all this special crisis care. It's hard to tell. One thing's clear though: self-report is not the whole story.
Gromann PM, Goossens FA, Olthof T, Pronk J, and Krabbendam L (2012). Self-perception but not peer reputation of bullying victimization is associated with non-clinical psychotic experiences in adolescents. Psychological medicine, 1-7 PMID: 22895003
Morthorst B, Krogh J, Erlangsen A, Alberdi F, and Nordentoft M (2012). Effect of assertive outreach after suicide attempt in the AID (assertive intervention for deliberate self harm) trial: randomised controlled trial. BMJ (Clinical research ed.), 345 PMID: 22915730