Table 1.
Overview of database searches.
Fig 1.
An explanation of the origin of the articles utilized in this study.
Table 2.
Projected growth of articles by category and article type.
The number of articles published in 2035 was predicted by exponential modeling, and modeling parameters for each category and article type are listed in the table.
Fig 2.
Article types (RA1, RA2, RA3) began to increase at different times during the past 7 decades.
This figure includes articles published through 2019.
Fig 3.
Distribution of article type and category.
(a) The pie-chart shows the distribution of included articles across the three research article types, RA1, RA2, and RA3. Within each research article type, RA1 (b), RA2 (c), and RA3 (d), the number of articles for each of the 8 categories were plotted as radial bar charts. It is important to note that some research articles were assigned more than one category, therefore the sum of the numbers for the 8 categories does not equal the number of included research articles.
Fig 4.
The percentage of total publications represented by each category has changed throughout the past 7 decades.
This figure includes articles published through 2019.
Fig 5.
Co-occurring category themes represented by a heatmap showing categories that were published together.
The number of articles is represented both as a color scale from light to dark green, as well as numbers on the heatmap, with light green being the lowest number of articles, and dark green indicating the highest number of articles. Only articles with 2 assigned categories were included in this analysis.
Fig 6.
This word cloud (WordItOut) indicates journals that have most frequently published RA1 articles.
To accommodate all journal titles on the word cloud, only those journals publishing three articles, or more, were included. Font size directly correlates to the number of articles published. Journal names with the same font color published the same number of articles (link to word cloud).
Table 3.
Top ten journals by article type across the seven decades studied.
Journals marked with a (*) indicate the top five journals of the last decade (2010–2019).
Table 4.
Citation metrics from RA1 and RA2 articles published between 2014–2021.
Table 5.
The 10 most frequently cited papers in 2014–2021.
Fig 7.
A graphical representation of the most commonly occurring author-selected keywords from the SCOPUS® literature search.
The size of the circle and word font directly correlates to the frequency of keyword occurrence in the dataset. This map produced 4 clusters of frequently co-occurring keywords (Table 7) and are differentiated by color. Line thickness corresponds to keyword co-occurrence frequency. Mixed line colors indicate the algorithm could not make clear distinctions between the clusters.
Fig 8.
A graphical representation of the most commonly occurring index-selected keywords from the SCOPUS® literature search.
The size of the circle and word font directly correlates to the frequency of keyword occurrence in the dataset. This map produced 3 clusters of frequently co-occurring keywords (Table 8) and are differentiated by color. Line thickness corresponds to the keywords co-occurrence frequency. Mixed line colors indicate the algorithm could not make clear distinctions between the clusters.
Table 6.
Four clusters of frequently co-occurring, author-selected keywords identified through VOSViewer.
Table 7.
Three clusters of co-occurring, index-selected keywords identified through VOSViewer.
Table 8.
Occurences of author-supplied versus index-supplied keywords.