bradford: Bradford's law

Description

It estimates Bradford's law source distribution and tests the goodness of fit.

Usage

bradford(M)

Value

The function bradford returns a list containing the following objects:

`table`		a dataframe with the source distribution partitioned in the three zones
`graph`		the Bradford bibliograph plot in ggplot2 format
`graph_shiny`		the Bradford bibliograph plot for biblioshiny (without logo)
`zoneSummary`		a dataframe summarizing the three Bradford zones
`stat`		a list of statistical results (coefficients, R2, KS test, Bradford multiplier)

Arguments

M: is a bibliographic dataframe.

Details

Bradford's Law of Scattering, first formulated by Samuel C. Bradford in 1934, describes the phenomenon of concentration and dispersion in scientific publishing: a small number of core journals account for a disproportionately large share of the literature on a given topic, while the remaining literature is scattered across an increasingly large number of peripheral journals.

If journals are ranked in decreasing order of productivity and partitioned into three zones, each containing roughly one-third of the total articles, the number of journals in each zone follows the ratio 1:n:n^2, where n is the Bradford multiplier.

The Bradford distribution models the cumulative number of articles C(r) contributed by the top r sources as: C(r) = a + b * log(r)

Reference:
Bradford, S. C. (1934). Sources of information on specific subjects. Engineering, 137, 85-86.

Examples

Run this code

if (FALSE) {
data(management, package = "bibliometrixData")

BR <- bradford(management)
}