qmb.plot {qmethod}

Q Methodology: Plot of bootstrap results

Description

Plots the summary of bootstrap results, either z-scores or factor loadings.

Usage

qmb.plot(qmbsum, type = c("zsc", "loa"), nfactors, 
         cex = 0.7, cex.leg = 0.8, errbar.col = "black",
         lwd = 1, lty = 1, vertdist = 0.2, limits = NULL, 
         r.names = NA, sort = c("none", "difference", "sd"),
         sbset = NULL, leg.pos = "topleft", 
         bty = "n", plot.std = TRUE, pch= NULL,
         col=NULL, grid.col="gray", ...)

Arguments

qmbsum

an object with the summary of bootstrap results, as produced by qmb.summary.

type

the subject to plot, either z-zcores of statements or factor loadings of Q-sorts.

nfactors

number of factors extracted.

cex

a numerical value giving the amount by which plotting text and symbols should be magnified relative to the default (see par).)

cex.leg

a numerical value giving the amount by which the legend should be magnified relative to cex.)

errbar.col

colour used for the error bars. Defaults to "black".

lwd

line width (see par).

lty

line type (see par).

vertdist

distance between the values for each factor.

limits

axis limits for the numerical values. If set to NULL, the limits are automatically set as c(-1, 1) when type = "loa", and as the minimum and maximum values of z-scores (including the error bars) when type = "zsc"

r.names

names of the items to be printed in the axis ticks(either Q-sorts when type = "loa", or statements when type = "zsc"). When the value is NULL, it defaults to rownames.

sort

ordering of the items in the axis. If set to "none", items are ordered by the default order in the dataset. If set to "difference", items are ordered according to the variability in the values across factors. If set to "sd", items are ordered according to the sum of the errors obtained in the bootstrap.

sbset

How many items are to be printed? When the value is NULL, it plots all the items.

leg.pos

Position of the legend.

bty

Legend box (see legend).

plot.std

logical value. When set to TRUE (default), it prints the points for values obtained with the standard analysis (non bootstrapped).

pch

plotting symbols. Defaults to NULL, in which case the symbols are selected automatically. If provided, the vector needs to contain at least as many elements as number of factors. In addition, if argument plot.std == TRUE (default) the vector needs to contain at least double as many elements as vectors, in order to extract (a) the plotting symbols for bootstrapped values (the first elements) and (b) the plotting symbols for standard values (the next elements).

col

colours for the points. At least as many elements as number of factors have to be provided.

grid.col

colour of the grid.

...

additional arguments to be passed to the functions dotchart, mtext, segments, points, abline or legend.

Author(s)

Aiora Zabala

References

Zabala, Pascual (2016) Bootstrapping Q Methodology to Improve the Understanding of Human Perspectives. PLoS ONE 11(2): e0148087.

See Also

qmethod, qmboots, qmb.summary

Examples

data(lipset)
boots <- qmboots(lipset[[1]], nfactors = 3, nsteps = 50,
                load = "auto", rotation = "varimax", 
                indet = "qindet", fsi = TRUE)
                
boots.summary <- qmb.summary(boots)

qmb.plot(boots.summary, 3, type = "loa", sort="difference")