Here is a study published in the American Journal of Infection Control that attempts to tackle the above question.The study utilized 2 online surveys, one for authors (n = 102) and one for Editorial Board members (n = 20) to assess their perspectives on the quality and timeliness of peer review.
Authors of accepted manuscripts were significantly more likely to rate the review as the same or better than other peer reviews they had received when compared with authors of rejected manuscripts (93.3% vs 47.4%, respectively, P = .001).Board members were significantly more likely to rate reviewers as fair and unbiased (91.4% and 70%, respectively, P = .04).
But what make a good reviewer? Well the data are sparse.Here is a perspective (free, fulltext) in JAMA on the assessment of a good journal reviewer. Surveys of reviewers of 420 manuscripts were completed by journal editors and authors. Using logistic regression analysis, the only significant factor associated with higher-quality ratings by both editors and authors was reviewers trained in epidemiology or statistics and younger age (40-60 yrs).
I review a fair number of manuscripts, am trained in epidemiology and am young (between 40-60). Let's hope that the quality of my journal reviews do not disappoint.