Mapping Science - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 291

Tabl e 8. 12 Survival analysis of time to retraction

Mean a

Median
95 % confidence interval 95 % confidence interval
Estimate Std. error Lower bound Upper bound Estimate Std. error Lower bound Upper bound
2.578

0.066 2.448 2.707 2.000 0.052 1.898 2.102

a Estimation is limited to the largest survival time if it is censored

The provision of full text articles would make it possible to study the context
of citations to a retracted article with computational tools. It would also make it
possible to study higher-level patterns of citations and how they change over time
with reference to retraction events.
We address these three questions and demonstrate how visual analytic methods
and tools can be developed and applied to the study of citation networks and citation
contexts involving retracted articles. There are many other issues that are important
to study but we decide to focus on the ones that are relatively fundamental.

8.3.2 Time to Retraction

In the Web of Science, the title of a retracted article includes a suffix of “ Retracted
article .” As of 3/30/2012, there are 1,775 records of retracted articles. The distribu-
tion of the 1,775 retracted articles since 1980 shows that retractions appear to have
peaked in 2007 with 254 retracted articles recorded in the Web of Science alone.
On the other hand, it might be still too soon to rule out the possibility of more
retrospective retractions.
It is relatively straightforward to calculate on average how long it may last
before the retraction of an article since its publication. It is common that the time
of retraction of an article is retrievable from the amended title of the article. For
example, if the title of an article published in 2010 is followed by a clause in the
form of (Retracted article. See vol. 194, pg. 447, 2011), then we know that the
article was retracted in 2011. We loaded the data into a built-in relational database
of CiteSpace and used the substring function in SQL to extract the year of retraction
from the title by counting backwards, i.e. substring (title, 5, 4). We found that the
mean time to retraction is 2.57 years, or 30 months, based on the retraction time
of the 1,721 retracted articles, excluding 54 records with no retraction date. The
median time to retraction is 2 years, i.e. 24 months (See Table 8.12 ).
Figure 8.11 shows a plot of the survival function of retraction. The probability
of surviving retraction reduces rapidly for the first few years since publication.
In other words, the majority of retractions took place within the first few years.
The probability of survival is below 0.2 for a 4-year old eventually to be retracted
article.