The continued use of retracted, invalid scientific literature.

Little is known about the ultimate scientific fate of retracted, invalid literature. We identified 82 completely retracted articles by electronic and manual methods and measured their subsequent use in the scientific literature by performing citation analysis. After retraction, these studies were cited, for support of scientific concepts, 733 times. Comparison with a control group revealed that retraction reduces subsequent citation by approximately 35%. There was no evidence that small, obscure journals, non-US journals, or non-US authors were disproportionately responsible for these citations. Although, after retraction, US authors accounted for a smaller percentage of citations, they continued to be the single greatest source. Several possible reasons why invalid information continues to be used were identified. These included a dearth of available information on retracted works; inconsistency in retraction format, terminology, and indexing; and an apparent lack of sufficient attention to manuscripts by some authors and editors.