| Type: | Package |
| Title: | Analysis and Visualization Likert Items |
| Version: | 1.3.5 |
| Date: | 2016-12-29 |
| Author: | Jason Bryer <jason@bryer.org>, Kimberly Speerschneider <kimkspeer@gmail.com> |
| Maintainer: | Jason Bryer <jason@bryer.org> |
| URL: | http://jason.bryer.org/likert, http://github.com/jbryer/likert |
| BugReports: | https://github.com/jbryer/likert/issues |
| Description: | An approach to analyzing Likert response items, with an emphasis on visualizations. The stacked bar plot is the preferred method for presenting Likert results. Tabular results are also implemented along with density plots to assist researchers in determining whether Likert responses can be used quantitatively instead of qualitatively. See the likert(), summary.likert(), and plot.likert() functions to get started. |
| License: | GPL-2 | GPL-3 [expanded from: GPL] |
| LazyLoad: | yes |
| VignetteBuilder: | utils |
| Depends: | R (≥ 3.0),ggplot2,xtable |
| Imports: | psych,reshape2,gridExtra,grid,plyr |
| Suggests: | devtools,shiny |
| RoxygenNote: | 5.0.1 |
| NeedsCompilation: | no |
| Packaged: | 2016-12-30 23:54:48 UTC; jbryer |
| Repository: | CRAN |
| Date/Publication: | 2016-12-31 01:37:00 |
Likert Analysis and Visualization
Description
Likert Analysis and Visualization
Author(s)
Pre-summarized results from an administration of the Math Anxiety Scale Survey.
Description
A data frame of presummarized results of the Math Anxiety Scale Survey administered to 20 students in a statistics course.
Format
data frame with 14 rows and 6 columns.
References
Bai, H., Wang, L., Pan, W., & Frey, M. (2009). Measuring mathematics anxiety: Psychometric analysis of a bidimensional affective scale. Journal of Instructional Psychology, 36 (3), 185- 193.
Pre-summarized results from an administration of the Math Anxiety Scale Survey grouped by gender.
Description
A data frame of presummarized results of the Math Anxiety Scale Survey administered to 20 students in a statistics course grouped by gender.
Format
data frame with 28 rows and 7 columns.
References
Bai, H., Wang, L., Pan, W., & Frey, M. (2009). Measuring mathematics anxiety: Psychometric analysis of a bidimensional affective scale. Journal of Instructional Psychology, 36 (3), 185- 193.
Absolute value formatter for continuous_scale
Description
This will print the absolute value for labeling on axis. Usefull for stacked bar plots where negative values are not negative percentages but represent negative groups.
Usage
abs_formatter(x)
Arguments
x |
value to be reformatted. |
Value
the absolute value of x.
Adapted from ggExtra package which is no longer available. This is related to an experimental mlpsa plot that will combine the circular plot along with the two individual distributions.
Description
Adapted from ggExtra package which is no longer available. This is related to an experimental mlpsa plot that will combine the circular plot along with the two individual distributions.
Usage
## S3 method for class 'plots'
align(gl, ...)
Arguments
gl |
grid.layout |
... |
graphic elements to combine. |
References
http://groups.google.com/group/ggplot2/browse_thread/thread/1b859d6b4b441c90 http://ggextra.googlecode.com/svn/trunk/R/align.r
Fictitious dataset with importance and satisfaction results across five different offices.
Description
This data set is used in the GapAnalysis demo and is used to demonstrate
how the likert package handles a gap analysis.
Format
a data frame with 68 ovservations of 11 variables.
Wrap label text.
Description
Wrap label text.
Usage
label_wrap_mod(value, width = 25)
Arguments
value |
vector (converted using |
width |
the maximum width of each line in characters. Adapted from https://github.com/hadley/ggplot2/wiki/labeller |
Analyze Likert type items.
Description
This function will provide various statistics about a set of likert items. The resulting object will have the following items:
Usage
likert(items, summary, grouping = NULL, factors = NULL, importance,
nlevels = length(levels(items[, 1])))
Arguments
items |
data frame containing the likert based items. The variables in the data frame should be factors. |
summary |
a pre-summarized data frame. The first column must be the items and the remaining columns are the levels (e.g. strongly disagree, disagree, etc). |
grouping |
(optional) should the results be summarized by the given grouping variable. |
factors |
a vector with |
importance |
a data frame of the same dimensions as items containing an importance rating for each item. The order of columns should match and the names from items will be used. |
nlevels |
number of possible levels. Only necessary if there are missing levels. |
Details
-
results- this data frame will contain a column 'Item', 'Group' (if a grouping variable was specified, and a column for each level of the items (e.g. agree, disagree, etc.). The value within each cell corresponds to the percentage of responses for that level and group. -
items- a copy of the original items data frame. -
grouping- a copy of the original grouping vector. -
nlevels- the number of levels used in the calculations.
Value
a likert class with the following elements: results, items, grouping, nlevels, and summary.
See Also
plot.likert
summary.likert
Examples
data(pisaitems)
items29 <- pisaitems[,substr(names(pisaitems), 1,5) == 'ST25Q']
names(items29) <- c("Magazines", "Comic books", "Fiction",
"Non-fiction books", "Newspapers")
l29 <- likert(items29)
summary(l29)
plot(l29)
Bar Plot for Likert Items.
Description
Bar plot for the results of likert.
Usage
likert.bar.plot(l, group.order, center = (l$nlevels - 1)/2 + 1, ...)
Arguments
l |
results of |
group.order |
the order in which groups (for grouped items) or items (for non-grouped items) should be plotted. |
center |
specifies which level should be treated as the center. For example,
|
... |
passed to |
likert |
object of type likert. |
See Also
plot.likert
likert.heat.plot
likert.bar.plot
likert.density.plot
Creates a density plot for likert items.
Description
This funciton will create a visualization that treats the likert items as a continuous variable.
Usage
likert.density.plot(likert, facet = TRUE, bw = 0.5, legend, ...)
Arguments
likert |
object of type likert. |
facet |
for non-grouped items, should each density distribution be plotted in a separate facet. |
bw |
the smoothing bandwidth. This is often set to the standard deviation but this is often inadequate for Likert type items. The value of 0.5 is used since the difference between any two adjacent levels is one. |
legend |
title for the legend. |
... |
parameters passed to |
See Also
plot.likert
Internal method.
Description
Internal method.
Usage
likert.heat.plot(likert, low.color = "white", high.color = "blue",
text.color = "black", text.size = 4, wrap = 50, ...)
Arguments
likert |
object of type likert. |
low.color |
color for low values. |
high.color |
color for high values. |
text.color |
color of text attributes. |
text.size |
size of text attributes. |
wrap |
width to wrap label text for non-grouped likert objects. |
... |
currently unused. |
See Also
plot.likert
likert.bar.plot
Histogram of number of responses.
Description
Plots a histogram of the number of responses for each item and group (if specified). Negative values (in maroon by default) indicate the number of missing values for that item and group.
Usage
likert.histogram.plot(l, xlab = "n", plot.missing = TRUE,
bar.color = "grey70", missing.bar.color = "maroon",
label.completed = "Completed", label.missing = "Missing",
legend.position = "bottom", wrap = ifelse(is.null(l$grouping), 50, 100),
order, group.order, panel.arrange = "v", panel.strip.color = "#F0F0F0",
text.size = 2.5, ...)
Arguments
l |
results of |
xlab |
label used for the x-axis. |
plot.missing |
if TRUE, missing values will be plotted to the left of the x-axis. |
bar.color |
the bar color. |
missing.bar.color |
the color of the bar for missing values. |
label.completed |
the label to use in the legend representing the count of complete values. |
label.missing |
the label to use in the legend representing the count of missing values. |
legend.position |
location of the legend. |
wrap |
number of characters before warping the text in the panel strips. |
order |
the order of the items. |
group.order |
the order in which groups (for grouped items) or items (for non-grouped items) should be plotted. |
panel.arrange |
v for vertical or h for horizontal. |
panel.strip.color |
the color for panels. |
text.size |
text size. |
... |
other ggplot2 parameters. |
Matrix plot (experimental)
Description
Matrix plot (experimental)
Usage
likert.matrix.plot(likert, nSample = nrow(likert$items), ...)
Arguments
likert |
results of |
nSample |
random sample of all rows. This function may take a while
to run with large datasets (including the |
... |
parameters passed to |
Builds an object with options for plotting likert results.
Description
Builds an object with options for plotting likert results.
Usage
likert.options(low.color = "#D8B365", high.color = "#5AB4AC",
neutral.color = "grey90", neutral.color.ramp = "white", colors = NULL,
plot.percent.low = TRUE, plot.percent.high = TRUE,
plot.percent.neutral = TRUE, plot.percents = FALSE, text.size = 3,
text.color = "black", centered = TRUE, include.center = TRUE,
ordered = TRUE, wrap = 50, wrap.grouping = 50, legend = "Response",
legend.position = "bottom", panel.arrange = "v",
panel.strip.color = "#F0F0F0", ...)
Arguments
low.color |
color for low values. |
high.color |
color for high values. |
neutral.color |
color for middle values (if odd number of levels). |
neutral.color.ramp |
second color used when calling |
colors |
vector specifying the colors to use. This must be equal to the number of likert levels. |
plot.percent.low |
whether to plot low percentages. |
plot.percent.high |
whether to plot high percentages. |
plot.percent.neutral |
whether to plot netural percentages. |
plot.percents |
whether to label each category/bar. |
text.size |
size of text attributes. |
text.color |
color of text attributes. |
centered |
if true, the bar plot will be centered around zero such that the lower half of levels will be negative. |
include.center |
if TRUE, include the center level in the plot otherwise the center will be excluded. |
ordered |
reorder items from high to low. |
wrap |
width to wrap label text for item labels |
wrap.grouping |
width to wrap label text for group labels. |
legend |
title for the legend. |
legend.position |
the position for the legend ("left", "right", "bottom", "top", or two-element numeric vector). |
panel.arrange |
how panels for grouped likert items should be arrange.
Possible values are |
panel.strip.color |
the background color for panel labels. |
... |
included for future expansion. |
Results from an administration of the Math Anxiety Scale Survey.
Description
A data frame of results of the Math Anxiety Scale Survey administered to 20 students in a statistics course. This data frame contains the original data and can be used to verify the pre-summarized procedures.
Format
data frame with 14 rows and 6 columns.
References
Bai, H., Wang, L., Pan, W., & Frey, M. (2009). Measuring mathematics anxiety: Psychometric analysis of a bidimensional affective scale. Journal of Instructional Psychology, 36 (3), 185- 193.
Programme of International Student Assessment
Description
North American (i.e. Canada, Mexico, and United States) results from the 2009 Programme of International Student Assessment (PISA) as provided by the Organization for Economic Co-operation and Development (OECD). See http://www.pisa.oecd.org/ for more information including the code book.
Format
a data frame 66,690 ovservations of 81 variables from North America.
Source
Organization for Economic Co-operation and Development
Plots a set of likert items.
Description
This is an implementation of the S3 plot generic function. Based upon the
type parameter this function will call either likert.bar.plot,
likert.heat.plot, or likert.density.plot. See the
help pages for those functions for all the available parameters to customize
the aesthetics of the figure. Although those functions can be plotted directly,
we recommend call the generic plot function.
Usage
## S3 method for class 'likert'
plot(x, type = c("bar", "heat", "density"),
include.histogram = FALSE, panel.widths = c(3, 1), panel.arrange = "v",
panel.strip.color = "#F0F0F0", legend.position = "bottom", group.order,
panel.background = element_rect(size = 1, color = "grey70", fill = NA), ...)
Arguments
x |
the likert items to plot |
type |
the type of plot to create. Current values are bar and heat. |
include.histogram |
if TRUE, a histogram of count of responses is also plotted. |
panel.widths |
if |
panel.arrange |
how panels for grouped likert items should be arrange.
Possible values are |
panel.strip.color |
the background color for panel labels. |
legend.position |
the position for the legend ("left", "right", "bottom", "top", or two-element numeric vector). |
group.order |
the order in which groups (for grouped items) or items (for non-grouped items) should be plotted. |
panel.background |
define background of the plot. See |
... |
other parameters passed passed to |
See Also
Plots a set of likert items.
Description
This is an implementation of the S3 plot generic function. Based upon the
type parameter this function will call either likert.bar.plot,
likert.heat.plot, or likert.density.plot. See the
help pages for those functions for all the available parameters to customize
the aesthetics of the figure. Although those functions can be plotted directly,
we recommend call the generic plot function.
Usage
## S3 method for class 'likert.gap'
plot(x, type = c("bar", "density"),
include.histogram = FALSE, panel.widths = c(3, 1), panel.arrange = "v",
panel.strip.color = "#F0F0F0", legend.position = "bottom",
panel.background = element_rect(size = 1, color = "grey70", fill = NA),
satisfaction.label = "Satisfaction", importance.label = "Importance",
legend, ...)
Arguments
x |
the likert items to plot |
type |
the type of plot to create. Current values are bar and heat. |
include.histogram |
if TRUE, a histogram of count of responses is also plotted. |
panel.widths |
if |
panel.arrange |
how panels for grouped likert items should be arrange.
Possible values are |
panel.strip.color |
the background color for panel labels. |
legend.position |
the position for the legend ("left", "right", "bottom", "top", or two-element numeric vector). |
panel.background |
define background of the plot. See |
satisfaction.label |
label used for satisfaction items. |
importance.label |
label used for importance items. |
legend |
title for the legend. |
... |
other parameters passed passed to |
See Also
Prints results table.
Description
Prints results table.
Usage
## S3 method for class 'likert'
print(x, ...)
Arguments
x |
the likert class to print. |
... |
parameters passed to |
Print method for likert.bar.plot. The primary purpose is to
suppress the "Stacking not well defined when ymin != 0" warning printed
by ggplot2 for bar plots that have negative bars (i.e. the centered
plots).
Description
Print method for likert.bar.plot. The primary purpose is to
suppress the "Stacking not well defined when ymin != 0" warning printed
by ggplot2 for bar plots that have negative bars (i.e. the centered
plots).
Usage
## S3 method for class 'likert.bar.plot'
print(x, ...)
Arguments
x |
a plot from |
... |
other parameters passed to ggplot2. |
Prints results table.
Description
Prints results table.
Usage
## S3 method for class 'likert.gap'
print(x, ...)
Arguments
x |
the likert class to print. |
... |
parameters passed to |
Print method for likert.heat.plot.
Description
Print method for likert.heat.plot.
Usage
## S3 method for class 'likert.heat.plot'
print(p, ...)
Arguments
p |
a plot from |
... |
other parameters passed to ggplot2. |
Prints the results of xtable.likert.
Description
Print method for xtable.likert.
Usage
## S3 method for class 'xlikert'
print(x, tabular.environment = "longtable",
floating = FALSE, ...)
Arguments
x |
results of |
tabular.environment |
see |
floating |
see |
... |
other parameters passed to |
Recode a vector.
Description
This utility function will recode values from an original character
or factor vector with new values.
Usage
recode(x, from, to, to.class = NULL)
Arguments
x |
the vector whose values will be recoded. |
from |
the old values in x to be recoded. |
to |
the new values. |
to.class |
an 'as.' function representing the desired vector type (i.e. as.character, as.numeric, as.logical, as.numeric). |
Value
a vector with same length of x with recoded values.
Examples
test <- letters[sample(5, 10, replace=TRUE)]
recode(test, from=letters[1:5], to=paste('Letter', letters[1:5]))
Reverse the levels of a factor.
Description
Reverse the levels of a factor.
Usage
reverse.levels(x)
Arguments
x |
a factor or a data.frame of factors whose levels will be reverse coded. |
Examples
mylevels <- c('Strongly Disagree', 'Disagree', 'Neither', 'Agree', 'Strongly Agree')
test <- factor(sample(mylevels[1:5], 10, replace=TRUE))
cbind(test, as.integer(test), as.integer(reverse.levels(test)))
Results from the Survey of Academic Self-Regulation (SASR).
Description
The Survey of Academic Self-Regulation (SASR) is comprised of six factors: self-regulation, intrinsic motivation, extrinsic motivation, self-efficacy, metacognition, and personal relevance and control.
Format
a data frame with 860 ovservations of 63 variables.
References
Dugan, R., & Andrade, H. (2011). Exploring the construct validity of academic self-regulation using a new self-report questionnaire. The International Journal of Educational and Psychological Assessment, 7(1).
Shiny App for the likert package.
Description
This will start a shiny app included with the package to show many of the features available in the likert package.
Usage
shinyLikert()
References
http://rstudio.com/shiny
Prints summary table of a Likert analysis.
Description
The summary function returns a data frame that provides additional
information. It contains 'Item' and 'Group' columns similiar to the results data
frame as well as a column 'low' corresponding to the sum of levels below
neutral, a column 'high' corresponding to the sum of levels above
neutral, and columns 'mean' and 'sd' corresponding to the mean and
standard deviation, respectively, of the results. The numeric values
are determined by as.numeric which will use the values of the factors.
Usage
## S3 method for class 'likert'
summary(object, center = (object$nlevels - 1)/2 + 1,
ordered = TRUE, ...)
Arguments
object |
the likert class to summarize. |
center |
specifies which level should be treated as the center. For example,
|
ordered |
whether the results should be ordered. Currently unsupported for grouped analysis. |
... |
currently unused. |
Prints summary table of a Likert analysis.
Description
The summary function returns a data frame that provides additional
information. It contains 'Item' and 'Group' columns similiar to the results data
frame as well as a column 'low' corresponding to the sum of levels below
neutral, a column 'high' corresponding to the sum of levels above
neutral, and columns 'mean' and 'sd' corresponding to the mean and
standard deviation, respectively, of the results. The numeric values
are determined by as.numeric which will use the values of the factors.
Usage
## S3 method for class 'likert.gap'
summary(object, ...)
Arguments
object |
the likert class to summarize. |
... |
parameters passed to |
Value
a list with two data frames with summarized data for satisfaction and importance results separately.
Prints a LaTeX table of the likert items.
Description
Crate a LaTeX or HTML table of the likert results.
Usage
## S3 method for class 'likert'
xtable(x, caption = NULL, label = NULL, align = NULL,
digits = NULL, display = NULL, auto = FALSE, include.n = TRUE,
include.mean = TRUE, include.sd = TRUE, include.low = TRUE,
include.neutral = (x$nlevels%%2 != 0), include.high = TRUE,
include.levels = TRUE, include.missing = TRUE, center = (x$nlevels -
1)/2 + 1, ordered = TRUE, ...)
Arguments
x |
likert class object. |
caption |
the table caption. |
label |
the table label. |
align |
column alignments. |
digits |
number of digits to use for numeric columns. |
display |
column formats. |
auto |
Logical, indicating whether to apply automatic format when no
value is passed to align, digits, or display (see |
include.n |
option to include n |
include.mean |
option to include mean |
include.sd |
option to include sd |
include.low |
option to include low |
include.neutral |
option to include neutral |
include.high |
option to include high |
include.levels |
option to include levels |
include.missing |
option to include missing levels. |
center |
specifies which level should be treated as the center. For example,
|
ordered |
whether the results should be ordered. See |
... |
other parameters passed to xtable. |
See Also
xtable, print.xtable
The zero grob draws nothing and has zero size.
Description
The zero grob draws nothing and has zero size.
Usage
zeroGrob()
Author(s)
hadley
References
https://github.com/hadley/ggplot2/blob/master/R/grob-null.r