SSACHR: Serial Sexual Assault Study Criminal History Records Paper Research Compendium

This package and corresponding GitHub repository are intended to enhance the reproducibility of a research paper (Campbell, Pierce, Goodman-Williams, & Feeney, 2021) by serving as a research compendium (Marwick, Boettiger, & Mullen, 2018). The principal investigator for the study is Dr. Rebecca Campbell (Professor, Department of Psychology, Michigan State University). The paper presents descriptive data about the criminal histories of suspected serial sexual offenders using data from both criminal history records and forensic DNA testing of sexual assault kits (SAKs).

Installation

The SSACHR package is available from a public repository available on GitHub at https://github.com/sjpierce/SSACHR. It was made public after the manuscript was accepted for publication.

Order of Installation Tasks

Before installing SSACHR, make sure you have:

• Installed R 4.1.2 or later. You can get the most recent version of R from the Comprehensive R Archive Network (CRAN).
• Installed any tools required for compiling packages (they will be specific to your operating system). These will be necessary for the devtools package to work. You may find Bryan & Hester’s (n.d.) website useful, especially the Set up an R dev environment section.
  • On Windows, see https://cran.r-project.org/bin/windows/Rtools/.
  • On Mac OS X, see https://cran.r-project.org/bin/macosx/tools and https://mac.R-project.org/tools/.
• Installed the devtools package for R. The most recent CRAN release will likely be more stable but sometimes you may instead need the development version at GitHub.
• Updated your R packages. You may be prompted with a dialog box asking “Do you want to install from sources the packages which need compilation?” It usually works fine if I choose “no”. Occasionally, it appears necessary to choose “yes”, but I am more likely to run into problems when doing that.
• Obtain the SSACHR repository from GitHub and review its contents.
• Install the SSACHR package to your R package library.
• Install additional R packages from CRAN.
• After installing SSACHR, see the Obtaining Data Files section below. You will need to download the data from an archive and put them in the right subfolder on your computer.

Obtain the Repository from GitHub

If you use Git (Torvalds et al., 2022) and have a GitHub account, either clone or fork and clone the package to your computer using the usual Git commands (Bryan, 2018; Bryan et al., 2019, Chapters 28 and 32). Otherwise, manually download a ZIP file and unzip its contents to a folder. Either way, the files should end up in a folder called SSACHR on your computer. That folder is your local copy of the repository.

Note that the package code uses relative rather than absolute folder path and file name references. Moving or renaming subfolders and/or files may cause problems. We have tested it only with the folder structure and file naming used in the primary repository on GitHub.

Understanding the Repository Structure and Contents

The structure for the package is shown in the outline below, where folder names and file names are highlighted like this and comments are in normal text. The folder structure is largely determined by the conventions governing the structure of R packages. It deviates a bit from the example research compendium folder structures discussed by Marwick et al. (2018). The repository is also set up as an RStudio project.

• SSACHR: This is the root folder for the repository.
  • data: This folder is where the data file produced by the script Step_01_Data_Mgt.Rmd will be stored. This is a standard folder for R package structures.
    • CHR_Data.RData is the data file produced by the script Step_01_Data_Mgt.Rmd after it imports the external data files. It is not distributed with the repository (see the Obtaining Data Files section).
    • Read_This_Nate.text This text file is just present to ensure that the data subfolder will be created when you clone the repository or extract files from ZIP file copy of the repository obtained from GitHub.
  • inst: This folder is where you can find the key files you will need to use if you want to re-run our analyses on your own computer. The unintuitive name for this folder is a result of R package building conventions (it is where you put files that should be installed with the package).
    • extdata: This subfolder is where you will need to put the SPSS data files mentioned in the Obtaining Data Files section below.
      • Read_This_Note.txt: This text file is just present to remind you
        that the extdata subfolder is where you should put the SPSS data files after you get them.
      • TWindow_Scenarios.csv: This file contains hypothetical data used by Step_01_Data_Mgt.Rmd to generate a figure.
    • compact-title.tex: This LaTeX file is used when you knit .Rmd files into PDF files. It helps control title section formatting.
    • Development_Tools.R: This file just contains R code reminders that I use while developing packages.
    • Step_01_Data_Mgt.pdf: This is the default output filename produced by knitting Step_01_Data_Mgt.Rmd. It is not distributed with the package because you would just generate it on your own computer to check reproducibility.
    • Step_01_Data_Mgt_Published.pdf: This is a copy of the final output I produced on my computer when preparing to release the package to the public. We relied on it to create our manuscript. It is distributed with the package because you may want to compare it to the results you get on your own computer by knitting Step_01_Data_Mgt.Rmd.
    • Step_01_Data_Mgt.Rmd: Knitting this file requires that you have already obtained the data files mentioned in the Obtaining Data Files section below. It performs initial data management steps to prepare the data for use in other scripts.
    • Step_02_Analysis.pdf: This is the default output filename produced by knitting Step_02_Analysis.Rmd. It is not distributed with the package because you would just generate it on your own computer to check reproducibility.
    • Step_02_Analysis_Published.pdf: This is a copy of the final output I produced on my computer when preparing to release the package to the public. We relied on it to create our manuscript. It is distributed with the package because you may want to compare it to the results you get on your own computer by knitting Step_02_Analysis.Rmd.
    • Step_02_Analysis.Rmd: This file should be knitted after you knit Step_01_Data_Mgt.Rmd because it depends on a data files created by that script. It will produce a PDF file called Step_02_Analysis.pdf.
    • R_Citations.pdf: This is the default output filename produced by knitting R_Citations.Rmd. It is not distributed with the package because you would just generate it on your own computer to check reproducibility.
    • R_Citations_Published.pdf: This is a copy of the final output I produced on my computer when preparing to release the package to the public. It describes the software environment I used to generate the files upon which our published manuscript was based. You can compare it to the environment on your computer. Maximum reproducibility should occur when you are using the environment described in this document.
    • R_Citations.Rmd: This file generates details about the R packages used by Step_01_Data_Mgt.Rmd and Step_02_Analysis.Rmd. I recommend knitting it after you knit those two files. When you knit it, you will get an output file called R_Citations.pdf showing the citations and versions for what is installed and in use on your computer.
  • man: This folder contains R help files (*.Rd) for the package and its custom functions. It is required by R package building conventions.
  • R: This folder contains the source code for the package’s custom functions in a set of *.R script files. It is required by R package building conventions.
  • .gitignore: This file tells Git what files to ignore and omit from synchronizing with the main repository on GitHub.
  • .Rbuildignore: This file tells R what files to ignore when building the package from the source code.
  • DESCRIPTION: This file is a brief, structured description of the package that is required by R package building conventions.
  • LICENSE: This file contains the terms of the CC-BY-SA-4.0 license that applies to all non-source code content in this repository.
  • LICENSE.md: This file contains the terms of the GPL3 software license that apply to the source code in this repository.
  • LICENSE.note: This file contais a notes explaining why there are are multiple licenses by specifying which content repository/package content falls under each license.
  • NAMESPACE: This file is created automatically by R when building the package. You should not edit it manually. It is required by R package building conventions.
  • NEWS.md: This file contains an list of comments about the changes made with each version of this package. It is required by R package building conventions
  • README.md: This file is obtained by knitting the README.Rmd file and is used by GitHub to display information about the package. Do not edit it manually. In R Studio, you can read the formatted version by opening the file and clicking the Preview button.
  • README.Rmd: This file gives an introduction to the package. Knitting it produces the README.md file and opens the preview automatically.
  • SSACHR.Rproj: This is an RStudio project file. It contains some settings for working with the project in that software.

Install SSACHR to Your R Package Library

Parts of the SSACHR package rely on custom functions defined in the package repository’s SSACHR/R subfolder. The easiest way to use them is to install the package to your personal R package library. Downloading or cloning the repository files to your computer does not install that package into your R package library. It just creates your local copy of the repository files.

To install the package to your R package library, you have to either build and install the package from those local files, or install it directly from GitHub.

The following code will install SSACHR directly from the Github repository into your personal package library by using the install_github() function from devtools.

devtools::install_github("sjpierce/SSACHR", ref = "main")

Install Additional R Packages from CRAN

Scripts in this R package depend on having a number of other R packages installed. Those packages are available from CRAN and can be installed by running the following code in the R console.

install.packages(pkgs = c("assertthat", "car", "descr", "dplyr", "emmeans", 
                          "geepack", "git2r", "ggdist", "ggplot2", "haven", 
                          "here", "kableExtra", "knitr", "lattice", 
                          "latticeExtra", "lubridate", "plyr", "psych", 
                          "rmarkdown", "RColorBrewer", "sjlabelled", "texreg",
                          "tinytex", "tidyr", "utils", "vistime", "xfun"))

Obtaining Data Files

The data files required by this package were deposited into the National Archive of Criminal Justice Data (Campbell, 2019). Please visit the web page for that deposit at NACJD to download the files.

After you have downladed the data from NACJD, unzip all the SPSS data files (*.sav) into the SSACHR/inst/extdata subfolder of your local repository. That should allow you to reproduce the analyses by re-running our scripts.

Once you have completed this step and all the others listed above, you should be ready to use this package to reproduce our results.

Loading the SSACHR Package in R

After it has been installed to your package library as described above, you can load SSACHR via the following R console command. That provides access to the custom R functions we have included in the package.

library(SSACHR)

Get Help on SSACHR’s Custom Functions

You can see information about the package by using the following command in the R console. The resulting help page has an Index link at the bottom that will show you a list of all the custom functions in the package.

?SSACHR

Reproduce Our Results

If you are using RStudio Desktop, the easiest way to start reproducing our results is to navigate to the SSACHR folder containing the repository and open the project file SSACHR\SSACHR.Rproj.

Then you can open and knit the key scripts in the following order:

• SSACHR/inst/Step_01_Data_Mgt.Rmd
• SSACHR/inst/Step_02_Analysis.Rmd
• SSACHR/inst/R_Citations.Rmd

To do that from the R console, the following code should work. Each call to Rscript_call() runs the listed input script in a fresh R session and writes a PDF output file to the specified name and folder inside the local repository. That will replace any prior version of the output by overwriting the file.

library(xfun)      # for Rscript_call()
library(here)      # for here()
library(rmarkdown) # for render()
Rscript_call(fun = render,
             args = list(input = here("inst/Step_01_Data_Mgt.Rmd"),
                         params = list(LogFile = "Step_01_Data_Mgt.pdf"),
                         output_file = "Step_01_Data_Mgt.pdf",
                         output_dir = here("inst")))
Rscript_call(fun = render,
             args = list(input = here("inst/Step_02_Analysis.Rmd"),
                         params = list(LogFile = "Step_02_Analysis.pdf"),
                         output_file = "Step_02_Analysis.pdf",
                         output_dir = here("inst")))
Rscript_call(fun = render,
             args = list(input = here("inst/R_Citations.Rmd"),
                         params = list(LogFile = "R_Citations.pdf"),
                         output_file = "R_Citations.pdf",
                         output_dir = here("inst")))

Software Information

We use R Markdown to enhance reproducibility because it provides excellent support for generating dynamic reports (Mair, 2016). Knitting the source R Markdown script README.Rmd generates this Markdown file. Knitting our other R Markdown scripts from this package generates PDF output files containing explanatory text, R code, plus R output (both text and graphics).

• We use RStudio 2021.9.1.372 or later to work with R and R markdown files. The software chain looks like this: Rmd file > RStudio > R > rmarkdown > knitr > md file > pandoc > tex file > TinyTeX > PDF file.
• We use pandoc 2.14.0.3 or later for this document. A version of pandoc comes bundled with RStudio, but if you want the most recent version, download it from https://pandoc.org/.
• We recommend using TinyTeX to compile LaTeX files produced by pandoc into PDF files. However, it may be viable to use MiKTeX or some other LaTeX distribution instead.

References

Bryan, J. (2018). Excuse me, do you have a moment to talk about version control? The American Statistician, 72(1), 20-27. doi:10.1080/00031305.2017.1399928

Bryan, J., The STAT 545 TAs, & Hester, J. (2019). Happy Git and GitHub for the useR. Retrieved from https://happygitwithr.com

Campbell, R. (2019). Serial sexual assaults: A longitudinal examination of offending patterns using DNA evidence, Detroit, Michigan, 2009 [Data files, codebooks, computer programs, and statistical output]. ICPSR37134-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2019-02-28. Retrieved from: https://doi.org/10.3886/ICPSR37134.v1

Campbell, R., Pierce, S. J., Goodman-Williams, R., & Feeney, H. (2022). A window of opportunity: Examining the potential impact of mandatory sexual assault kit (SAK) testing legislation on crime prevention [Manuscript accepted for publication]. Psychology, Public Policy, and Law.

Mair, P. (2016). Thou shalt be reproducible! A technology perspective. Frontiers in Psychology, 7(1079), 1-17. doi:10.3389/fpsyg.2016.01079

Marwick, B., Boettiger, C., & Mullen, L. (2018). Packaging data analytical work reproducibly using R (and friends). The American Statistician, 72(1), 80-88. doi:10.1080/00031305.2017.1375986

Torvalds, L., Hamano, J. C., & other contributors to the Git Project. (2022). Git for Windows (Version 2.34.1) [Computer program]. Brooklyn, NY: Software Freedom Conservancy. Retrieved from https://git-scm.com

Funding Support

This R package and repository are based on research supported by the following grant.

Campbell, R., Pierce, S. J., & Sharma, D. (2015–2018). Serial sexual assaults: A longitudinal examination of offending patterns using DNA evidence. (NIJ Award # 2014-NE-BX-0006) [Grant]. National Institute of Justice.

Disclaimer

This research was supported by a grant from the National Institute of Justice, United States (2014-NE-BX-0006). The opinions or points of view expressed in this document (or any other document included in this R package and repository) are solely those of the authors and do not reflect the official positions of any participating organization or the U.S. Department of Justice.

Citing This Package

Please cite the package itself, plus the associated data files and the journal article.

Pierce, S. J. (2022). SSACHR: Serial sexual assault study criminal history records paper research compendium. (Version 1.0.0) [Reproducible research materials and computer program, R package]. GitHub and Zenodo. https://github.com/sjpierce/SSACHR and https://doi.org/10.5281/zenodo.5854874

Campbell, R. (2019). Serial sexual assaults: A longitudinal examination of offending patterns using DNA evidence, Detroit, Michigan, 2009 [Data files, codebooks, computer programs, and statistical output]. ICPSR37134-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2019-02-28. Retrieved from: https://doi.org/10.3886/ICPSR37134.v1

Campbell, R., Pierce, S. J., Goodman-Williams, R., & Feeney, H. (2022). A window of opportunity: Examining the potential impact of mandatory sexual assault kit (SAK) testing legislation on crime prevention [Manuscript accepted for publication]. Psychology, Public Policy, and Law.