Friday, July 30, 2010

Research Proposals and Confusion about Dependent Variables

The following blog posting was originally uploaded to my hub here:

Having taught a year-long, two-course research component to Kean students for the past few years, it has become apparent that one of the most nagging issues for students is the dependent variable. Consider the following:

"My research proposal is about whether the death penalty reduces murder, so my dependent variable would be whether or not states have capital punishment, right?"


Research methods textbooks aren't necessarily helpful. Yes, they give the definition but even when my students do the reading, I can see from the blank stares that what they've read isn't sinking in. Here's a sampling of definitions for dependent variables from a few methods books:

From Singleton & Straits (2010), Approaches to Social Research: "The dependent variable is the one the researcher is interested in explaining and predicting. Variation in the dependent variable is thought to depend on or to be influenced by certain other variables. The explanatory variables that do the influencing and explaining are called independent. If we think in terms of cause and effect, the independent variable is the presumed cause and the dependant variable is the presumed effect."

From Maxfield & Babbie (2011), Research Methods for Criminal Justice and Criminology: "The variable assumed to depend on or be caused by another variable (called the independent variable). If you find that sentence length is partly a function of the number of prior arrests, then sentence length is being treated as a dependent variable."

And from my beloved Bachman & Paternoster (1997) Statistical Methods for Criminology and Criminal Justice: "Dependent variable - the variable that is being affected or influenced by another variable. It is often denoted as y. In a causal analysis the dependent variable is caused by the independent variable."

See a common theme in these definitions? The variables pertain to cause and effect. In the social sciences (like CJ, sociology and psychology), the effects are often people's behavior. In criminal justice field, those behaviors of interest would be..... crime! Crime. Antisocial behavior. Violence. Bad things that people do.

How do we measure our dependent variable crime? There are various ways, including arrests, victimization data (people reporting that they were harmed), and self-report criminal behavior (what people tell you they did criminally, for which they may or may not have been caught).

So to return to the original research question "Does capital punishment reduce crime?" the dependent variable would be crime, specifically states' arrest rates.
Other examples:

(1) Research question: Does the such-and-such conflict resolution program make schools safer?

Dependent variable: measure(s) of school safety such as # of fights, # of times the police are called to a school, # of suspensions for fighting.

(2) Research question: Does Colorado's anti-bullying law reduce bullying in school?

Dependent variable: measure(s) of bullying in school, such as data gathered through surveys of students about whether they've been bullied, done any bullying, or witnessed any bullying

(3) Research question: Does mandatory arrest by police reduce domestic violence (DV)?

Dependent variable: measure(s) of domestic violence reoffending (for instance)

(4) Research question: Which makes neighborhoods safer, having the police drive through the area or walk the beat on foot?

Dependent variable: measure(s) of neighborhood crime, such as home burglaries

Wednesday, July 14, 2010

Welcome Back! Looking ahead to Fall 2010 Seminar

To my many, many incoming CJ_4600/Senior Seminar students:

Welcome to the course! I look forward to meeting all of you in just over a month. Some of you I already know, either from Research Methods or another course. In any case, welcome, welcome, welcome.

Two words: don't worry.

Senior Seminar is the course many students dread. Why? It's a lot of work. You probably haven't done anything like this - execute a research study - before. You've heard horror stories from other students.

I'll try and reassure you - it'll be fine. Really. You'll live through it. There will be a lot of you, but I try to give each student about 30 minutes of one-on-one time throughout the semester.

Let me give you a quick picture of the shape of the semester. The first four weeks are spent gearing up to submit your research proposals. If you haven't done so already, you'll take Kean IRB's human subjects protection course and submit to me your course completion certificate. You'll also do a series of in-class and homework exercises that will give you a feel for the various research methods you'll have the option of using for your study. By about week five of the course you'll submit to me your research proposal.

Very Important Point: While this proposal will undoubtely be similar to the proposal you submitted in CJ_3675, it will not be identical to that proposal. CJ_4600 is a different course. You'll need to revise your CJ_3675 proposal to fit the requirements of CJ_4600. We'll go over this more in class. This is just a heads-up.

I typically grade the proposals in about a week, then return them to the students. You'll either be Approved to Begin, Approved-With-Revisions to Begin, or Not Approved. For the non-approved students, you'll have a week to fix the problems and then you'll meet with me again to explain what you did. By about the 7th or 8th week in the semester, everyone should have begun their data gathering.

By about the 10th or 11th week in the semester, the entire class goes to the computer lab to begin data entry and preliminary analyses. In my experience, this is when most students need a lot of hand-holding from the professor. I will get to each and every one of you, and only ask that you remember that there's only one of me and 25 of you in every class. So just be patient. I'll get to you, I promise.

By week 13 or 14, the final papers are due. During the last two classes, students present their findings to their fellow classmates and me. I'll send everyone a template powerpoint presentation to use as a model for their own slides.

One final point, which you'll probably hear me say in class too - everything I'm asking you to do, I've done myself. Proposal writing - check. Surveys and focus groups - check. Content analysis - check. Analyzing existing databases - check. This summer I'm doing both a content analysis and analyzing data from an existing database. I wouldn't ask you to do anything that I myself didn't have a hands-on feel for, if that's any consolation.

In a nutshell, that's it. I promise you'll survive and move on to graduation. And if you have any plans to attend graduate school (hello, Kean MA in CJ program, having done an original research study like what you'll do in CJ_4600 will help your application. If you like doing the kinds of research work we'll do in Seminar, then graduate school might be for you.

Enjoy the rest of your summer, and I'll see you in September.


Dr. Hassett-Walker