Jeromy Anglim's Blog: Psychology and Statistics

Friday, October 30, 2009

How to Reason about Causes in Psychology | When does Correlation Co-occur with Causation?

This post is on causal inference. Errors in causal inference in the social and behavioural sciences are prevalent both in the scientific literature and in the media. This post (a) suggests articles on causality to read, particularly for researchers in psychology; (b) discusses and critiques material on the Internet on causality; and (c) provides further links to material on causality.

Thursday, October 29, 2009

Tips for Using StatET and Eclipse for Data Analysis in R

My favourite editor for conducting analysis in R is the StatET plug-in for Eclipse. This post discusses an assortment of tips and tricks that I've discovered to make this editing environment even better.

Monday, October 26, 2009

Scale Construction | Item Reversal, Scale Scores, Reliability, and Metadata

This post discusses how to: (a) use exploratory factor analysis output to determine items to retain on a test; (b) run syntax that reverses items and produces scale scores for a test; (c) calculate reliabilities for scales using retained items. Various tips are provided to make the process more efficient and less error-prone. The example uses SPSS, but many of the ideas would generalise to other statistics packages.

Exploratory Factor Analysis and Scale Construction | R, SPSS, and General Resources

In this post I provide links to resources on exploratory factor analysis and scale construction. Links are provided for conducting exploratory factor analysis in R and in SPSS. Links to academic articles on the topic of exploratory factor analysis and scale construction with an emphasis on psychological applications are provided.

Depth Interviews | Applications, Thoughts, Resources

This post discusses depth interviews. The post: (a) provides a range of applications where interviews may be useful; (b) makes a few observations from my experience; (c) lists additional resources for the interested reader.

Saturday, October 24, 2009

Data Mining and R

This post lists a few data mining resources in R. I also provide a few observations on the distinction between data mining, data analysis, and statistics as it pertains to the analysis work that I do in psychology.

Friday, October 23, 2009

Syntax Tips for Efficient Variable Selection in SPSS

This post discusses a few tricks for efficiently using syntax in SPSS. The suggestions aim to make variable selection more efficient and less error-prone. Specifically, an example is given of how to efficiently run a reliability analysis on a set of scales. The post is aimed at researchers using SPSS who are just starting to learn about the importance of Syntax.

Wednesday, October 21, 2009

Introduction to Twitter | One Academic's First Steps

I have just started using Twitter. This post documents my experience. My aim is to give some suggestions to others who might be considering the adoption of Twitter.

Tuesday, October 20, 2009

Comments on "Data Intensive Scientific Discovery"

An interesting book has been published free online on the future of the scientific method and the role of computing, software, and information systems: Data Intensive Scientific Discovery
The ideas link in with the concerns of myself and others with reproducible research, data sharing, data analysis, and open publishing.

What's in a Name? 21st Century Problems: Searching for PASW version 18

Most people now know that IBM has acquired SPSS, and SPSS the software product has changed it's name to PASW. I have often observed name changes with interest. Kentucky Fried Chicken (at least in Australia) decided long ago to change its name to KFC, possibly because Kentucky was too American, Fried implied  fat and unhealthy food, and chicken was too limiting. Likewise, SPSS decided long ago to distance itself from being just a statistics package for the social sciences.

IBM has now released version 18 of PASW. I was trying to find out what were the new features in version 18, when I stumbled on a potential problem with the new name, and perhaps some reasons why IBM may want to move out of troubling teen version numbers as quickly as possible.

Focus Groups Should Not Be Used to Measure Attitudes of the Population | Myki Case Study

Victoria is in the process of adopting a new public transport ticketing system called Myki based on an electronic card. It's delivery is late and the project is over budget. The system has become a political issue. It was interesting to read the following statement:
"[MyKi project’s new spokeswoman] said that Government focus groups had shown that Melburnians were looking forward to using the new card." - TheAge
I just wanted to make a few comments about problems in the reasoning of the above quote.

Monday, October 19, 2009

Getting Started with Social Network Analysis

I have presented research on social network analysis to several forums including to organisational and educational psychology audiences. In these settings the audience varies substantially in their prior exposure to social networks analysis. Researchers new to social network analysis often then ask me where they should start in order to learn about the theories and methods of social network analysis. This post aims to provide some links to get such an interested researcher started.

How to conduct a social network analysis: A tool for empowering teams and work groups

In 2007 I presented a talk discussing ways that social network analysis could be used as a consulting tool to improve team functioning. I'd earlier done some consulting work with Lea Waters applying social network analysis to understand team dynamics in professional white-collar teams. The experience highlighted the value of social network analysis as well as several of the methodological and practical issues that arise when using social network analysis as a consulting tool. The slides from the talk are made available to anyone interested.

Job Satisfaction | Measurement, Scales, Facets

I was just reading through a section on job satisfaction in Landy and Conte's 2010 I/O psychology textbook Work in the 21st Century (3rd edition). The aim of this post is to comment on theories of job satisfaction and issues associated with job satisfaction measurement. I use Landy and Conte's text book (my favourite I/O textbook) as a frame of reference to guide discussion.

Comments on the "R Clinic"

Theresa Scott runs an R Clinic at Vanderbilt. Researchers bring their questions along to weekly sessions and some answers are posted on this website.  It's great to see the combination of statistical consulting services and public posting of answers for the benefit of all.
Theresa has also developed a set of course notes on R, R Commander, Latex and Sweave, and Excel.

Analysing ordinal variables

Ordinal variables create challenges for analysis. This post discusses: (a) definitions and distinctions related to ordinal variables, (b) theoretical issues related to ordinal variables, and (c) options for analysing ordinal variables.

Friday, October 9, 2009

Comments on "Ecological Statistics with R"

Didrik Vanhoenacker has put together a site called Ecological Statistics with R.

Introduction to SPSS Syntax | Advice for Conducting Reproducible Research

This post provides an overview of SPSS syntax for researchers using SPSS. It sets out (1) why it is important to use syntax, (2) tips on how to use and learn syntax, (3) tips on dealing with errors; 4) tips on organising your syntax, (5) additional resources to learn more, and (6) where to go after you have reached the limits of SPSS syntax.

Thursday, October 8, 2009

Follow Up Tests in ANOVA in SPSS

This post discusses how to run follow up tests in ANOVA.

Wednesday, October 7, 2009

Factor Analysis in R

This post shows an example of running a basic factor analysis in R.

Exporting R data to Excel

Learnr discusses the various options for exporting R data into Excel.

Efficient Variable Selection in R

This post sets out my procedure for efficiently and reliably selecting variables from a data.frame in R

Monday, October 5, 2009

Blogs That I Follow

Besides Blogs on R, these are some blogs that I follow:

Including R Code in a Blog Post

This post discusses ways of including formatted code in a blog post.

Practical Tips on How to Conduct a Sophisticated Online Psychological Experiment

This post discusses strategies for conducting an online psychological experiment. The material was written in May 2008, and I have not yet got round to publishing it in an official outlet, and perhaps I never will. It's mainly just practical advice. Thus, it is provided online with the aim of sharing the ideas. I have other posts on Inquisit where I share sample scripts.

My Software Setup

This post sets out the software that I am currently using.

Analysis of a Multiple Choice Test | Getting Started

This post discusses how to perform a basic reliability analysis of a multiple choice test.

Sunday, October 4, 2009

Calculating Scale Scores for Psychological Tests

This post discusses how to calculate scale scores for multi-item scales. A lot of psychological research uses multi-item scales (e.g., personality tests, symptoms check lists, surveys, etc.). This post focuses on the issues involved with computing these scale scores.

Producing a Table of Item Descriptive Statistics

The following post sets out how to present a table of descriptive statistics for a set of items using SPSS, Excel, and Word. At the bottom of the post, I've got an example of doing it in R.

Saturday, October 3, 2009

Creating Instructional Videos and getting Screen Captures with Jing

This post discusses one way of getting screen captures from your desktop and creating short instructional videos of actions on a computer.

Scoring a Multiple Choice Test in SPSS using DO REPEAT

How do you score a multiple choice test in SPSS? This post shows you how.

Data Mining and Statistics Video Course

David Mease has an online course presented with complete videos (Statistics 202: Statistical Aspects of Data Mining ). The course uses Excel and R.

Friday, October 2, 2009

Newspaper Reports IQ to be 180 | Is it True?

I was reading TheAge. Google is bringing out Google Wave. As part of the story they interview an Australian engineer on the project:
"Nigel, who has an IQ of 180, is also a maths whiz.." - The Age
This got me thinking. What does it mean to have a 180 IQ. IQ is a norm score. IQ typically has a mean of 100 and a standard deviation of 15. Thus, I asked the following questions:

  • What's the probability of having an IQ of 180 or higher?
  • One in how many people would have an IQ 180 or higher?
  • What's is the probability that someone who a newspaper reports as having a 180 IQ or higher, actually has an IQ of 180 or higher?

Windows XP Virtual Desktop Manager

This post discusses how to set up multiple virtual desktops on Windows XP. Some of the benefits are also discussed.