Friday, March 30, 2007

Help with, Statistics

Just plowed through a new book that I think will be immensely helpful for folks in any of the following categories:

a) Don't understand statistics
b) Have never taken a statistics course
c) Think ANOVA is a new type of star
d) Find reading journal articles to be a unique brand of torture
e) Would like to go to an I/O or HR conference but don't speak "research"

The book is "Understanding statistics: A guide for I/O psychologists and human resource professionals" by Michael Aamodt, Michael Surrette, and David Cohen.

The purpose of the book, in the words of the authors, is "to provide students and human resource professionals with a brief guide to understanding the statistics they encounter in journal articles, technical reports, and conference presentations."

On the whole, the authors do an amazing job. Considering they use under 120 pages (and we're not talking dictionary font here), they cover a lot of ground, including:

- The basics, such as data types, measures of central tendency, and variability
- Sample size
- Standard scores
- Testing for differences between groups (e.g., t-tests, ANOVA, Chi-Square)
- Correlation and regression
- Meta-analysis
- Factor analysis

The language used throughout is mostly very easy to understand. The examples used are relevant and the authers make good use of humor when they can. The book focuses on how to interpret statistics rather than how to calculate them. Is there room for improvement? I think so, particularly in the ANOVA and regression sections, where it tends to get a little "stats speak." But overall this is a great primer for people who would like to (or need to) understand I/O and HR research.

One of the authors, Dr. Mike Aamodt, was kind enough to answer a few questions I had about the book:

BB: What inspired you to write this book? How do you hope it gets used?

MA: At IPMAAC meetings I noticed that many of the attendees were frustrated because they could not follow some of the statistics used in the presentations. So the inspiration for the book was to help HR professionals who don't have advanced degrees or lots of stat courses, feel comfortable listening to presentations or reading journal articles and technical reports. Our thinking was that, once you remove all the formulas and just concentrate on the meaning and use of statistics, it is not that scary.

We hope that the text will be used by HR professionals as well as by students. We think it would be a useful start to a stat class in which students would read our short text prior to reading a more in-depth text.

BB: How did you decide what topics to include? What got left out?

MA: Deciding what to include and omit was tough. We included the topics that seemed to be the most commonly used statistics in presentations and technical reports. Because the intended audience is "stat novices," we tried not to go too much in depth on any topic. Following such a plan was easier said than done, and we really had to resist the temptation to discuss everything about a topic. The book is only 120 pages and we thought that if it were much longer, we would lose the interest of the stat novice.

BB: Are there other texts you're planning on writing, or that you think should be written?

MA: I have several other texts I plan to write. I want to do a follow-up to the stat primer that gets into more detail but still omits formulas. I also plan to write a primer on conducting systemic compensation analyses, one on police selection, and one on employee selection in general. A book I think needs to be written is a practical, applied text on how to conduct a job analysis.

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