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  1. Make Power Fun (Again?) February 24, 2017

    Make Power Fun (Again?)

    Brandon LeBeau

    University of Iowa

    Tags:   slides R simglm package

  2. Use CSS to format markdown or HTML files January 3, 2017

    Markdown (and Rmarkdown) are great ways to quickly develop material without worrying about the formatting. The documents can then be compiled using the knitr or rmarkdown packages to output formats such as HTML, latex, or even word. The main drawback of this approach is that formatting of documents is limited to italics, bold, or strikethrough. Markdown does have support for inline HTML, therefore you can add your own formatting inline using CSS or other HTML attributes, however this moves away from the quick markdown flavor.

    Tags:   R package highlightHTML markdown HTML

  3. Introduction of the pdfsearch package December 2, 2016

    I'm happy to introduce an add-on package, pdfsearch, that adds the ability to do keyword searches on pdf files. This add-on package uses the excellent pdftools package from the ropensci project to read in pdf files and perform keyword searches based character strings of interest.

    Tags:   R pdfsearch package

  4. Extending accessibility of open-source statistical software to the masses A shiny case study October 7, 2016

    Extending accessibility of open-source statistical software to the masses: A shiny case study

    Brandon LeBeau

    University of Iowa

    Tags:   slides R shiny package

  5. Estimating NCAA Football Coaches’ Abilities An Application of Item Response Theory July 31, 2016

    Estimating NCAA Football Coaches’ Abilities An Application of Item Response Theory

    Brandon LeBeau, Andrew Zieffler, and Kyle Nickodem

    University of Iowa & University of Minnesota

    Tags:   slides IRT cfb GLMM

  6. Simulation and power analysis of generalized linear mixed models June 29, 2016

    Simulation and power analysis of generalized linear mixed models

    Brandon LeBeau

    University of Iowa

    Tags:   slides R simglm power simulation

  7. Assessing the validity of item response theory models when calibrating field test items April 9, 2016

    Assessing the validity of item response theory models when calibrating field test items

    Brandon LeBeau

    University of Iowa

    Tags:   slides IRT Field Test

  8. Informative vs uninformative prior distributions with characteristic curve linking methods April 8, 2016

    Informative vs uninformative prior distributions with characteristic curve linking methods

    Brandon LeBeau, Keyu Chen, Wei Cheng Liu, and Aaron McVay

    University of Iowa

    Tags:   slides IRT Linking

  9. AERA Poster 2016 Monte Carlo April 6, 2016

    I have a poster session at AERA http://www.aera.net/ on Monday, April 11. This paper explores design characteristics of Monte Carlo studies to include key simulation conditions as a part of the simulation design. The main advantage, it is argued, of this approach is a gain in generalizeability while still maintaining strong internal validity.

    Tags:   AERA Monte Carlo Poster

  10. Interactively building test forms from an IRT perspective An application of R and Shiny February 18, 2016

    Interactively building test forms from an IRT perspective: An application of R and Shiny

    Brandon LeBeau

    University of Iowa

    Tags:   R slides shiny buildform

  11. Web Scraping to Item Response Theory - A College Football Adventure December 4, 2015

    Web Scraping to Item Response Theory: A College Football Adventure

    Brandon LeBeau, Andrew Zieffler, and Kyle Nickodem

    University of Iowa & University of Minnesota

    Tags:   R slides rvest cfb

  12. Speed test of sequence generation for unbalanced simulation March 31, 2015

    I have a simulation package that allows for the simulation of regression models including nested data structures. You can see the package on github here: simReg. Over the weekend I updated the package to allow for the simulation of unbalanced designs. I'm hoping to put together a new vigenette soon highlighting the functionality.

    Tags:   R sequence speedtest

  13. Remove leading 0 with ggplot2. March 23, 2015

    I recently had an occasion while working on a three variable interaction plot for a paper where I wanted to remove the leading 0's in the x-axis text labels using ggplot2. This was primarily due to some space concerns I had for the x-axis labels. Unfortunately, I did not find an obvious way to do this in my first go around. After tickering a bit, I've found a workaround. The process is walked through below.

    Tags:   R graphics ggplot2

  14. Structured simulation of regression models - simReg package. October 1, 2014

    I'd like to introduce a package that simulates regression models. This includes both single level and multilevel (i.e. hierarchical or linear mixed) models up to two levels of nesting. The package produces a unified framework to simulate all types of continuous regression models. In the future, I'd like to add the ability to simulate generalized linear models. This package is an extension of the functions I used to simulate data for my dissertation.

    Tags:   R package simReg

  15. Google location data -- Where I've been. September 26, 2014

    I was emailed by a friend that was looking into their google location data and had asked if I had ever used a json file before in R. I said I had not, but I knew there were packages to do such things. The things I sent were things he had already tried, so what did I decide to do? I went ahead and downloaded my own google location data.

    Tags:   graphics R ggplot2 maps google

  16. Offense or defense improve likelihood of becoming bowl eligible? September 5, 2014

    I saw a post recently about the likelihood of a baseball team winning based on how many runs, hits, and other baseball statistics. I liked the idea and thought of applying that to college football. Particularly, I'm interested in knowing whether scoring more points or having a stout defense improves the likelihood of becoming bowl eligible.

    Tags:   graphics R ggplot2 cfb rCharts

  17. Dodged bar charts, why not a line graph? August 5, 2014

    I often see graphs that are poorly implemented in that they do not achieve their goal. One such type of graph that I see are dodged bar charts. Here is an example of a dodged bar chart summarizing the number of all star players by team (focusing specifically on the AL central division) and year from the Lahman r package:

    Tags:   graphics R ggplot2 trend

  18. Format Markdown Documents in R July 30, 2014

    Have you ever used a markdown file to create an html file? Have you ever wanted to quickly format the subsequent html file to add some color or other aspects? If your answer is yes to both of those questions, this package may be of interest to you.

    Tags:   R highlightHTML package CSS markdown html

  19. R gui Revisited May 27, 2014

    A couple months ago I wrote about switching my class from using SPSS to one that uses R with a gui frontend (original post). Since the semester has wrapped up, below are my thoughts on how the course went with respect to the students using R.

    Tags:   R gui

  20. AERA Preview April 2, 2014

    The American Educational Research Association (AERA) annual conference is this weekend in Philadelphia. I was lucky to have a paper accepted into the conference. I am presenting a meta analysis that I have been working on for the past two years or so titled: Model misspecification and assumption violations with the linear mixed model: A meta analysis.

    Tags:   R rCharts Javascript AERA

  21. Evolution of Code March 27, 2014

    Recently while scraping some data from the college football data warehouse site, I started to realize the evolution of my code. To preface this, I am definitely not a trained programmer, just a self taught junky who enjoys doing it when I have time. I've slowly evolved my programming skills from simply statistics languages like r or SPSS, to some other languages like LaTeX, HTML, CSS, Javascript, and I've started to work through some python.

    Tags:   R code XML evolution

  22. Update to highlightHTML package March 14, 2014

    I've added a new functionality to my highlightHTML package. This package post-processes HTML files and injects CSS and adds tags to create some further customization (for example highlight cells of a HTML table). This is most useful when writing a document using markdown and converting it into a HTML document using a tool like knitr, slidify, or even pandoc.

    Tags:   R highlightHTML markdown html

  23. rCharts with slidy March 3, 2014

    My last post I talked about using rCharts to create interactive graphics for my interview presentations. They seemed to go over pretty well in my interviews and helped me greatly as I did not need to remember or write down specific numbers to talk about. I use slidy to create my HTML slideshows and there was some interest from my last post to see exactly how I had these charts into a slidy html presentation.

    Tags:   R rCharts javascript html slidy

  24. Rcharts February 15, 2014

    ---layout: post title: Interactive charts with rCharts

    tags: [R, rCharts, javascript]

    Tags:  

  25. Picking a gui interface for R February 3, 2014

    Recently I decided to switch statistical programs used introductory statistics course for masters students that I teach at the University of Arkansas. Historically this course has been taught with SPSS, but I am attempting the switch to R this semester. Most students in this class have never used a statistical program before and have no programming background/interest. As a result, I did not want to have them learn statistics and the R language in the same semester and have them using R with a gui interface. The two primary gui systems/packages I explored were the Deducer package and the Rcmdr package. Here are my initial thoughts on the switch.

    Tags:   R gui

  26. When I use plyr/dplyr January 24, 2014

    My last post I talked about how I use the data.table package for aggregating and removing duplicate observations. Although I use the data.table package quite often, there are many times when I use plyr (and now the new dplyr) package, primarily because of its easy, intuitive syntax.

    Tags:   R plyr dplyr

  27. Two of my favorite data.table features January 6, 2014

    When I started to use the data.table package I was primarily using it to aggregate. I had read about data.table and its blazing speed compared to the other options from base or the plyr package especially with large amounts of data. As an example, I remember calculating averages or percentages while at Saint Paul Public Schools and while the calculations were running would walk away for 5 minutes to wait for them to finish. When using data.table to do the same calculations I didn't need to wait 5 minutes to see the calculated values.

    Tags:   R data.table

  28. Guessing Correlations: A shiny app December 30, 2013

    A recent hobby of mine (as with many other R users) is to play around with the relatively new R package: shiny. I started creating demo applications about a year ago just to figure out how powerful the platform could be, but it was not until this fall that I started creating some applications for others to use.

    Tags:   R shiny teaching

  29. SPSS to R: An R package to convert SPSS syntax November 26, 2013

    My first statistical software package I used as an undergrad was SPSS. I was fortunate during my senior year at Luther College to be initially introduced to R. I did not realize it at the time (except for the pretty graphics) that this was the start of something big for me. Fast forward a year to graduate school at the University of Minnesota and the majority of my program was again using SPSS. Under the tutelage of Andy in my first graduate statistics course I started to do analyses in both R and SPSS. After that I started to do all my analyses in R. Fast forward five years this time to my first full-time job after graduate school at Saint Paul Public Schools and again everyone was using SPSS. Fortunately in my year there I was able to significantly push them toward using R more and more.

    Tags:   R SPSS package

  30. My Course Slide Generation November 18, 2013

    This past August I took an opportunity to step back into the University academic world as a Visiting Assistant Professor at the University of Arkansas. I have enjoyed the transition back into the academic world, including a more flexible schedule, variation in topics/duties, and collaborating with colleagues.

    Tags:   R markdown LaTeX slidy

  31. Formatting Markdown Tables with R November 1, 2013

    This past summer when the twin cities R user group was starting to get back up and running, I offered to present on some R related things that I was working on. One thing I was working on was a part of my last post. In a response to discussing this during a meeting, I was posed with the problem of how to do this with a markdown table. I replied I was unsure how to do this directly with R, but it could likely be possible.

    Tags:   R markdown CSS

  32. Conditional Formatting Tables using R September 28, 2013

    One thing that I had the opportunity to develop while working last year at Saint Paul Public Schools was figuring out a quick, easy, and painless way to do interactive report generation. When I arrived in the REA department at Saint Paul Public Schools, the report generation process was roughly as follows:
    1. Do the analysis in SPSS (compute percent proficient for standard tests by various subgroups).
    2. Format output and copy output into Excel.
    3. Once in Excel, do lookup tables to generate the report in Excel.

    Tags:   R LaTeX

  33. Blog Logo September 11, 2013

    Welcome to my new website/blog. I am aiming to highlight some of the R packages that I have created. You can see a list of all the R packages I have in development and also see the source code on github here: R packages. In addition, I'll likely talk about various topics with statistics, teaching, research, or R in general.

    Tags:   R ggplot2