Research Design Paper

Research Design Paper

Mary Jones


March 6, 2017

Philip Russo

Research Design Paper

Research designs range from descriptive case studies to the experimental approach. Experimental designs usually produce the best results but are not always practical for many social science studies. This paper will give an explanation of internal and external variable-related validity factors. It will discuss the strengths and limitations of experimental research designs, as well as provide a summary of two contemporary examples of innovative research conducted within the criminal justice field within the past ten years.

Internal and External Variable-Related Validity

Internal validity refers to how well an experiment is done, and whether it avoids confounding. The less chance for confounding in a study, the higher its internal validity is. Internal validity refers to how well a piece of research allows you to choose among alternate explanations of something. Internal validity is a way to see how powerful your research methods were. External validity refers to how well data and theories from one setting can apply to another.External validity helps to answer the question: can the research be applied to the “real world”? If your research applies to other situations, external validity is high. If the research cannot be replicated in other situations, external validity is low (Internal Validity: Definitions and Examples, 2017.). External validity is the rationality of widespread implications in a relevant study, which is grounded on tests as investigational rationality. It is the degree to which the outcomes of an investigation can be applied to other circumstances and individuals. External validity is important, being that causal relationships can be widespread to various trials, people, surroundings, and periods.

The list of things that can have an effect on internal validity includes regression to the mean, pre-testing subjects, changing the instruments during the study, participants dropping out of the study, failure to complete protocols, and something unexpected changes during the experiment ( Internal Validity: Definitions and Examples, 2017).

Strengths and Limitations of Experimental Research Designs

According to “7 Advantages And Disadvantages Of Experimental Research” (2015), “there are multiple ways to test and do research on new ideas, products, or theories. With some of these ways being by experimental research. But this only happens when the researcher has complete control over one set of the variable and manipulates the others. However, if done properly, it is known as one of the most efficient and accurate ways to reach a conclusion.” ( 7 Advantages and Disadvantages of Experimental Designs, 2015)

Some of the strengths are a higher level of control by the ones conducting the experiment. There is a better chance in accurate results by isolating and determining what they are looking for. Experimental research can be used in many different types of situations and can span across almost all fields of research. Clear cut conclusions. With the high level of control and only one variable being tested at a time, the results are more relevant. There is a wide variety of experimental research, and each can provide different benefits.

Just like anything else, experimental research has its disadvantages. When it comes to research and experiments, an error is a big thing. Whether a systematic or random error or human error, they can all destroy the validity of the experiment. This type of research can take a huge amount of time and use large amounts of resources and finances since individual experiments have to be done to fully research each variable ( 7 Advantages and Disadvantages of Experimental research, 2015).

Contemporary examples

The Philadelphia Foot Patrol Experiment

According to “The Philadelphia Foot Patrol Experiment” “The Philadelphia Foot Patrol Experiment was a major research collaboration between the Philadelphia Police Department and researchers in Temple University’s Department of Criminal Justice involving over 200 police officers on foot beats around some of the city’s most violent corners.” (Ratcliffe, Taniguchi, Groff, and Wood, 2011). Using data from 2006 to 2008, researchers identified the areas of Philadelphia that had the highest violent crime rate. In the summer of 2009 officers patrolled each area on foot patrol, with two pairs assigned to each area from Tuesday to Saturday in two shifts. After three month’s violent crime had decreased 23%, drug-related detections increased by 15%, pedestrian stops increased 64%, vehicle stops increased 7%, and arrests increased 13%. The project won the 2010 Excellence in Law Enforcement Research Award from the International Association of Chiefs of Police and the Outstanding Experimental Field Trial Award from the American Society of Criminology’s Division of Experimental Criminology. According to Temple Universities Department of Criminal Justice (2015),follow-up research showed that “ Beats that were in place beyond three months had diminishing effects during the experiment, and effect not seen with the shorter term beats. Foot patrol beats returned to their pre-experiment crime levels once the foot patrol experiment was concluded.” (Philadelphia Foot Patrol Experiment, 2015)

Treatment for juveniles who sexually offend

Meta-analysis studies have found that sex-offender treatment works, especially multisystemic and cognitive-behavioral treatment approaches. Single studies have found at least modest treatment effects for both sexual and nonsexual recidivism. According to “Przybylski (2015) “, “sex offenders have received considerable attention in recent years from both policymakers and the public. Due to the profound impact that the sex crime has over the person. While most of the perpetrators of sex crimes are adults, a significant percentage of sexual offenders are under age 18.” (Przybylski, 2015). Juveniles who commit sexual crimes are diverse in their offending behaviors and future risk to public safety. Juvenile sexual offenders have more in common with other juvenile delinquents than they do with adult sexual offenders. Juveniles are more impulsive and less aware of the consequences of their behavior than adults. According to “Przybylski” (2015) “Worling and Curwen (2000), used a quasi-experimental design to examine the effectiveness of a specialized community-based treatment program that provided therapeutic services to adolescents and children with sexual behavior problems and their families. While treatment plans were individually tailored for each offender and his or her family, cognitive-behavioral and relapse prevention strategies were used, and offenders typically were involved in a concurrent group, individual, and family therapy. Recidivism rates were calculated using survival analysis for a treatment group consisting of 58 adolescents (53 males and 5 females) and a comparison group consisting of 90 adolescents (86 males and 4 females). Comparison group subjects consisted of three subgroups: juveniles who refused treatment, juveniles who received an assessment in the program only, and juveniles who dropped out of the community-based program prior to completing 12 months of treatment. To determine potential effects of group differences, the researchers also examined whether the treatment and comparison group subjects differed in any meaningful way on various factors related to recidivism (e.g., prior criminal history, offender demographics, victim characteristics); no significant differences between the treatment and comparison group subjects were found.  Based on a 10-year follow-up period, Worling and Curwen (2000) found that the juveniles in the treatment group had significantly better outcomes than comparison group members on several measures of recidivism. For example, the sexual recidivism rate was 5 percent for the treatment group compared to 18 percent for the combined comparison group. The recidivism rates for any offense were 35 percent for the treatment group and 54 percent for the combined comparison group. In fact, for every measure of recidivism employed in the study, the treatment group had lower recidivism rates than comparison group members who either refused treatment, received an assessment only or dropped out of the program prior to completing 12 months of treatment. In 2010, Worling, Litteljohn, and Bookalam reported findings from a follow-up analysis that extended the follow-up period for the original sample of study subjects to 20 years. Study subjects were, on average, 31.5 years old at the end of the 20-year follow-up period. The analysis demonstrated that the positive treatment effects originally observed by Worling and Curwen (2000) using a 10-year follow-up period had persisted over a longer period of time.” (Przybylski, 2015).


While experimental research has its advantages and disadvantages, it is still one of the best ways to get accurate results and is what is called “true research.” Experiments are done to predict a fact or situation. Experimental research is important to society; it helps us to improve our everyday lives. This paper discussedinternal and external variable-related validity factors. It also discussed the strengths and limitations of experimental research designs, as well as gave summaries of two contemporary examples of empirical research conducted within the criminal justice field within the past ten years.


7 Advantages and Disadvantages of Experimental Research. (2015). Retrieved from

Experimental Research. (2017). Retrieved from

Internal Validity: Definition and Examples. (2017). Retrieved from

Przybylski, R. (2015). Effectiveness of Treatment for Juveniles Who Sexually Offend . Retrieved


Ratcliffe, J. H., Taniguchi, T., Groff, E.R., & Wood, J. (2011). The Philadelphia Foot Patrol

Experiment: A randomized controlled trial of police patrol effectiveness in violent crime

hotspots. Criminology, 49(3), 795-831.

The Philadelphia Foot Patrol Experiment. (2015). Retrieved from