Trained Observer

Self-reports may not be a reliable source or the best way to retrieve information. People might tend to represent themselves in a positive light and do not always reflect on negative attributes or behaviors. Self-perception theory also comes into play when assessing ourselves through observations.

If I had to give superiority I would give it to observations of the person being assessed by a trained observer. I think that reports from close friends and family could be biased as well. Due to attachment, and love. Close friends and family would perhaps ignore the flaws. A trained observer or behaviorist understands personality well and could report based on expert opinion not biases.