About 35,000 papers may need retraction for doctored images


Doctored images spotted by Elisabeth Bik

Researchers have been able to spot inappropriately duplicated images in 59 of 960 papers published in one journal between 2009 and 2016. Of the 59, five were retracted. They conclude that nearly 35,000 papers containing doctored images are candidates for retraction. An earlier study found that higher proportion of papers containing problematic images were from China and India.

Visual screening of 960 papers published in the journal Molecular and Cellular Biology between 2009 and 2016 helped researchers find 59 (6.1%) papers that had “inappropriately duplicated images”. While image duplication in 42 papers were from errors during figure preparation and could be corrected, five of 59 papers (nearly 10%) were retracted as they either had manipulated images or too many problems that could not be fixed with a simple correction. No action was taken in the case of 12 papers due to several reasons. The pre-print findings were reported in bioRxiv.

Image duplications were categorised as 1) simple duplications, 2) duplication with repositioning or 3) duplication with alterations. While the first category is most likely to be due to an honest mistake, the two other categories have increased likelihood of deliberate falsification or fabrication. But even the first category involving simple duplication may result from misconduct if the image has been reused from a different experiment and published elsewhere.

“The figures were identified by [Elisabeth M. Bik] the lead author on the basis of inappropriate duplications.  She has a remarkable natural ability to identify both image duplication and image manipulation. The inappropriate duplications included errors in figure assembly as well as some that were probably intended to deceive. My impression is that majority of problems are the result of honest mistakes.  The fact that these papers could be corrected means that the figure problems did not affect the conclusions of the study,” Dr. Arturo Casadevall from Johns Hopkins School for Public Health, Baltimore and one of the authors of the paper told me in an email. “Even though manipulation with intent to mislead occurs in the minority of instances, when it occurs the consequences are very serious.”

Problematic images were inspected by two other authors and final confirmation was done using software.

In another paper published in June 2016 in the journal mBio, Dr. Bik and others looked for inappropriate duplication of Western blot images alone from over 20,500 papers published in 40 different journals from 1995 to 2014. Of the papers examined, 782 (3.8%) contained at least one figure containing duplicated image. At least 50% of the papers with inappropriate images were suggestive of deliberate manipulation.

“Since 3.8% [papers with inappropriate image duplication] was calculated on papers from 40 different journals with different impact factors, this percentage serves as a reasonable representation of the whole body of biomedical literature. The 10.1 % is the percentage of papers that were retracted in the Molecular and Cellular Biology dataset. Granted, this was a much smaller dataset than the one from the mBio paper, but it was a set that was seriously looked at,” Dr. Bik told Retraction Watch.

“If there are 8,778,928 biomedical publications indexed in PubMed from 2009-2016 and 3.8% of the papers contain a problematic image, and 10.6% of that group contain images of sufficient concern to warrant retraction, then we can estimate that approximately 35,000 papers are candidates for retraction due to image duplication,” they write in the paper reported in bioRxiv.

The authors state that 35,000 might be overestimation as not all papers would have images of the kind studied by them. At the same time, they warn that only visible duplications were studied and problems with graphs, tables and other datasets were not looked at, suggesting that the number of papers that might warrant retraction might be even more than 35,000.

“A well trained person can spot the same images in different papers.  The development of software to identify such images is a priority and would be helpful to the scientific publishing field,” says Dr. Casadevall.

India’s track record for image duplication

Of particular concern to India is the findings of the 2016 paper by Dr. Bik and others. Of the 40 journals studied, the authors looked for the country of origin for each of the 348 papers from PLOS ONE containing duplicated images. This analysis was restricted to PLOS ONE as it offered an online tool to search for geographic origin of the authors.


Countries plotted above the blue line had a higher-than-expected proportion of problematic papers.

While majority of PLOS ONE papers containing inappropriately duplicated images were from China and the U.S., the proportion of papers containing problematic images were higher from China and India. Whereas China had a 1.89-fold-higher probability of containing problematic images than predicted from the frequency of publication, India had 1.93 higher-than-predicted ratio of papers containing image duplication.

And as expected, the authors of papers with problematic images were repeat offenders. They found that in nearly 40% of the papers with duplicated images, papers by the same authors published in other journals showed revealed the same problem with images. The authors have not provided information about where these repeat offenders are from.

“Papers containing inappropriately duplicated images originated more frequently from China and India and less frequently from the United States, United Kingdom, Germany, Japan, or Australia,” they write. “This suggests that ongoing efforts at scientific ethics reform in China and India should pay particular attention to issues relating to figure preparation.”


The paper was published on July 23, 2018 in Molecular and Cellular Biology

Published in The Hindu on July 5, 2018