Hugh Pickens writes: "The image of scientists as objective seekers of truth is periodically jeopardized by the discovery of a major scientific fraud. Recent scandals like Hwang Woo-Suk's fake stem-cell lines or Jan Hendrik Schön's duplicated graphs showed how easy it can be for a scientist to publish fabricated data in the most prestigious journals. Daniele Fanelli has an interesting paper on PLOS One where she performs a meta-analysis synthesizing previous surveys to determine the frequency with which scientists fabricate and falsify data, or commit other forms of scientific misconduct. A pooled weighted average of 1.97% of scientists admitted to have fabricated, falsified or modified data or results at least once -a serious form of misconduct by any standard- and up to 33.7% admitted other questionable research practices. In surveys asking about the behavior of colleagues, admission rates were 14.12% for falsification, and up to 72% for other questionable research practices. Misconduct was reported more frequently by medical/pharmacological researchers than others. "Considering that these surveys ask sensitive questions and have other limitations, it appears likely that this is a conservative estimate of the true prevalence of scientific misconduct," writes Fanelli. "It is likely that, if on average 2% of scientists admit to have falsified research at least once and up to 34% admit other questionable research practices, the actual frequencies of misconduct could be higher than this.""