find_max_disp {tlda}R Documentation

Find the maximally dispersed distribution of an item across corpus parts

Description

This function returns the (hypothetical) distribution of subfrequencies that represents the highest possible level of dispersion for a given item across a particular set of corpus parts. It requires a vector of subfrequencies and a vector of corpus part sizes. This distribution is required for the min-max transformation proposed by Gries (2022: 184-191; 2024: 196-208) to obtain frequency-adjusted dispersion scores.

Usage

find_max_disp(subfreq, partsize, freq_adjust_method = "even")

Arguments

subfreq

A numeric vector of subfrequencies, i.e. the number of occurrences of the item in each corpus part

partsize

A numeric vector specifying the size of the corpus parts

freq_adjust_method

Character string indicating which method to use for devising dispersion extremes. See details below. Possible values are "even" (default) and "pervasive"

Details

This function creates a hypothetical distribution of the total number of occurrences of the item (i.e. the sum of its subfrequencies) across corpus parts. To obtain the highest possible level of dispersion, the argument freq_adjust_method allows the user to choose between two distributional features: pervasiveness (pervasive) or evenness (even). For details and explanations, see vignette("frequency-adjustment"). To obtain the highest possible level of dispersion, the occurrences are either spread as broadly across corpus parts as possible (pervasive), or they are allocated to corpus parts in proportion to their size (even). The choice between these methods is particularly relevant if corpus parts differ considerably in size. Since the dispersion of an item that occurs only once in the corpus (hapaxes) cannot be sensibly measured or manipulated, such items are disregarded; the function returns their observed subfrequencies.

Value

An integer vector the same length as partsize

Author(s)

Lukas Soenning

References

Gries, Stefan Th. 2022. What do (most of) our dispersion measures measure (most)? Dispersion? Journal of Second Language Studies 5(2). 171–205. doi:10.1075/jsls.21029.gri

Gries, Stefan Th. 2024. Frequency, dispersion, association, and keyness: Revising and tupleizing corpus-linguistic measures. Amsterdam: Benjamins. doi:10.1075/scl.115

Examples

find_max_disp(
  subfreq = c(0,0,1,2,5), 
  partsize = c(100, 100, 100, 500, 1000),
  freq_adjust_method = "pervasive")


[Package tlda version 0.1.0 Index]