R for Assessment Specialists: Glossary

Use RStudio to write and run R programs.

Use install.packages() to install packages (libraries).

Access individual values by location using [].

Access arbitrary sets of data using [c(...)].

Use logical operations and logical vectors to access subsets of data.

Use read_csv to read tabular data in R.

Use factors to represent categorical data in R.

Use the dplyr package to manipulate dataframes.

Use select() to choose variables from a dataframe.

Use filter() to choose data based on values.

Use group_by() and summarize() to work with subsets of data.

Use mutate() to create new variables.

Use the tidyr package to change the layout of dataframes.

Use gather() to go from wide to long format.

Use spread() to go from long to wide format.

ggplot2 is a flexible and useful tool for creating plots in R.

The data set and coordinate system can be defined using the ggplot function.

Additional layers, including geoms, are added using the + operator.

Boxplots are useful for visualizing the distribution of a continuous variable.

Barplot are useful for visualizing categorical data.

Faceting allows you to generate multiple plots based on a categorical variable.

psych are two packages that facilitate classical test theory analysis.

rcrtan facilitates criterion-referenced test and item analyses.

dplyr and tidy can be used to analyze the output of psychometric analysis.

Yes! You can apply this stuff to new data!

equate can be used for small- and large-sample test equating.

You can do item response modeling in R!

lavaan and semPlot are two useful packages for CFA.

Rmarkdown provides a flexible framework for analysis and reporting.

R and RStudio can be used to carry out reproducible test analyses and reporting.

You can apply stuff that you learned today!