Scoliosis: density-equalizing mapping and scientometric analysis

Abstract

Background: Publications related to scoliosis have increased enormously. A differentiation between publications of major and minor importance has become difficult even for experts. Scientometric data on developments and tendencies in scoliosis research has not been available to date. The aim of the current study was to evaluate the scientific efforts of scoliosis research both quantitatively and qualitatively.

Methods: Large-scale data analysis, density-equalizing algorithms and scientometric methods were used to evaluate both the quantity and quality of research achievements of scientists studying scoliosis. Density-equalizing algorithms were applied to data retrieved from ISI-Web.

Results: From 1904 to 2007, 8,186 items pertaining to scoliosis were published and included in the database. The studies were published in 76 countries: the USA, the U.K. and Canada being the most productive centers. The Washington University (St. Louis, Missouri) was identified as the most prolific institution during that period, and orthopedics represented by far the most productive medical discipline. "BRADFORD, DS" is the most productive author (146 items), and "DANSEREAU, J" is the author with the highest scientific impact (h-index of 27).

Conclusion: Our results suggest that currently established measures of research output (i.e. impact factor, h-index) should be evaluated critically because phenomena, such as self-citation and co-authorship, distort the results and limit the value of the conclusions that may be drawn from these measures. Qualitative statements are just tractable by the comparison of the parameters with respect to multiple linkages. In order to obtain more objective evaluation tools, new measurements need to be developed.

Figure 1

Scoliosis-related publications in the Web of Sciences database from 1904 to 2007.

Figure 2

A: Ranking of the total number of scoliosis-related publications per country. Threshold of >100 published items. Study period from 1904 to 2007. 2B: Density-equalizing map illustrating the number of publications per country. The area of each country was scaled in proportion to its total number of scoliosis-related publications for period 1904 to 2007.

Figure 3

Analysis of the international cooperation. Threshold >10 cooperative partnerships.

Figure 4

A: Average citations per item rate in each of the 20 countries with the highest citation rates. Study period from 1904 to 2007. 4B: Density-equalizing map showing the average citations per item in each country. Threshold excludes countries with <30 published items. The area of each country was scaled in proportion to its average citation rate. Study period from 1904 to 2007.

Figure 5

Citations per year compared to the published items in each year. Study period from 1904 to 2007.

Figure 6

A: Top ten ranking of journals by the number of publications and impact factor for items during the period from 1904 to 2007. 6B: Ten most productive authors and their h-index in the period from 1904 to 2007.

Figure 7

A: Top twenty list of the most productive medical disciplines for scoliosis research. Study period from 1904 to 2007. 7B: Most frequent medical disciplines of the ten most productive authors. Study period from 1904 to 2007.

Figure 8

A: Top fifteen ranking of the most productive institutions during the period from 1904 to 2007. 8B: Analysis of institutional cooperation. Threshold excludes institutions with <10 published items.