ScienceNews discussed the article in Science on plagiarism:
Suppose author #1 reported that in a few experimental trials, drug therapy worked as well as surgery. But he only had data exhibiting this success in three of the five patients treated. Still, that drug therapy cost only 2 percent as much as surgery and reduced recovery times by 90 percent. (...)Now what if another team reported comparing the same drug vs. surgery in a group of 200 patients — and described the same roughly 60 percent success rate for the drug? The second paper, in this instance a plagiarized report based on the first journal article (but containing bogus data), not only would lend credence to the initial finding, but also raise the drug treatment’s statistical strength, since it was now successful in a far larger population.
Note also the article by Don Vergano in USAToday: Scientists explain why they plagiarize, which includes the text:
"It's just too easy to cut and paste these days," says Harold Garner of the University of Texas Southwestern Medical Center in Dallas, an expert of scientific plagiarism.
In a report in the current journal Science, his team lists excuses offered by "potential" plagiarists, authors of studies in which the text was, on average, 86.2% similar to previously-published work.
Self-plagiarism is more common than plagiarism of third parties. SIU does not seem to care too much about either.