Quantitative Research in Criminal Justice


Criminal justice is a very important field in the study of law. It is a stage in the process of justice. It requires extensive research since it is the first stage in the process of giving justice to people who need it. There are many methods of research, and each one of them works best in specific areas. Quantitative research is one of these research methods. It uses samples and numerical values in making important didactic conclusions in life. This paper analyzes the application of quantitative methods of research in criminal justice.


Quantitative research entails the collection and conversion of data into numerics with the purpose of coming up with statistical computations and conclusions. This research uses two variables, the dependent and independent variables. The variables help the researchers in the manipulation of data before making conclusions (Gregg, 2007).

The researcher, usually, formulates questions that help in the development of hypotheses, predictions of the results. The researchers need to have instruments that measure the changes in the variables at the beginning and the end of the experiments. Besides, they also need to have proper schemes of their work to avoid mix-ups in the course of their studies.

Researchers use many methods in the collection of data. The methods they use in particular studies depend on the nature of the study and the variables. In modern times, computers have taken over every sector in research. Researchers use them in the collection and analysis of data. Therefore, compared to the previous centuries, the analysis of data has become very easy for the researchers. However, depending on the nature of the study, the involvement of the computer can be unnecessary. Some studies require more practical involvement of the researchers than computers (Gregg, 2007).

Quantitative research uses samples to generalize about large populations. Therefore, the scientist must eliminate all elements of bias in the formulation of their variables. They must also get rid of the influence of external factors. For example, if the research is about the impact of drinking on crime rate, the researchers must test the relationship between drinking and crime rate alone. They should not combine the effects of single parenthood and drinking.

In criminal justice, quantitative methods help in determining many realities. Researchers always assign numerical values to some concepts of criminal justice, making them variables. One concept becomes the independent variable while the other assumes the position of the dependent variable. They then attempt to establish a cause and effect relationships between the two variables (Gregg, 2007).

Various types of research require the use of quantitative research methods. They include survey, experimental, quasi-experimental, longitudinal, cross-sectional, meta-analysis and time series research (Stringer et al., 1999). This paper analyses the application of quantitative research methods in these types of research in criminal justice.

Types of Research


Survey involves the collection of responses from different people or groups of people about certain trends in the community. It mostly involves questioning the groups using questionnaires, emails, telephone calls and personal interactions. The questions may be open-ended, closed or a mixture of both open-ended and closed-ended questions. For example, the researcher can ask members of the community, “What do you think is the biggest cause of the increased crime rate in your community?” This question is open-ended; the respondents are free to mention whatever they believe is the biggest cause of high crime rates in their community.

The researchers can also formulate closed-ended questions such as, “Which of the following do you think is the biggest contributor to the increase in the rate of crime in your community?” The answers may include, A. Alcoholism, B. Poverty, C. Juvenile delinquency, C. Increase in the number of single parents. The respondents do not have the freedom to select whatever they think. They already have the options.

This method is the commonest research method today due to its flexibility and efficiency. It is also very economical and easy to generalize. However, it may give wrong results in case of bias in sampling, data collection and general formulation of the research. Researchers should be cautious in the selection of samples and the designing of the research.

Experimental Research

Many people support experimental research as the best method for analyzing the cause-effect relationship between variables. This method of study has two groups of participants, the experimental participants and the control group. It also involves the manipulation of one variable and anticipating an effect on the other variable. The research assigns the two comparison groups randomly (Dressler, 2002). In criminal justice, the researchers would have two groups; one group made up of youths who grew up with single parents and, on the other side, youths who grew up with both parents. They then would analyze their involvement of crime before making conclusions.

Many researchers, usually, carry out pre-tests and post-tests on the variables. Pre-tests analyze the autonomous variables prior to the investigation while the post-tests scrutinize the dependent variables after the manipulation of the autonomous variables. Some experimental designs involve carrying out pre-tests on independent variables and post-tests on both variables. For example, if two groups of police officers that are similar in everything took part in an investigation about the rate of crime in the community, the researchers would pre-test both of them with the purpose of obtaining information about the rate of crime.

They would also know about people’s thoughts on crime. The researchers would then manipulate the experimental group and post-test both groups after the experiment to determine the effects of the manipulation.

Quasi-Experimental Research

Quasi-Experimental research does not have a randomized assignment of variables. There are several types of quasi-experimental research. They include research that lacks equality in their control groups and the before-and-after models. Research models that have non-equivalent control groups have comparison and experimental groups that exist even before the manipulation of the variables. The researchers often create them randomly. The before-and-after groups have both tests but lack the comparison groups. For example, Watson studied the influence of police officers on the disregard for safety belts.

He chose two groups of police officers in the regions where police did not strictly enforce the safety belt law. He then popularized the campaign for the use of safety belts in the media and then tightened the enforcement of the regulation. In the end, the end, the observation of the safety-belt rule improved drastically among the experimental group, but nothing changed in the comparison group.

The before-and-after group is evident in the analysis that Pierce and Bowers made about the influence of the Massachusetts Bartle-Fox law about the use of guns. According to this law, unlicensed carriers of arms should get a year’s jail term. Their investigation revealed a decline in crimes that involved guns, but an increase in crimes that did not require guns.

Cross-sectional Research

This method of research involves a detailed analysis of one group at a time. Researchers use samples to make conclusions about large populations. This type of research is very common in criminal justice research. The best incident of cross-sectional study is Hirsh’s work on the roots of law breaking. He asked groups of men questions that related to delinquency and bonds among people (Gregg, 2007).

Longitudinal Research

In this type of research, researchers study a single group for a long time. Their main objective is analyzing the changes that occur in a group and between several groups. Longitudinal study has two sub-branches. The first sub-branch is panel st udy and the other one is cohort study. In the panel study, researchers stick to a single group for a long period. On the other hand, cohort studies stick to a more particular population and the transformations it undergoes over a given span of time (Dressler, 2002).

Researchers analyze the same participants one time or on several occasions. An example of longitudinal research is the NCSV interview on households in the US. They, usually, carry out random selections of households for interviews. Out of their seven groups, they always take a member from each every six months. Marvin Wolfgang investigated crime among youths by analyzing all teenagers who grew up in Philadelphia. Wolfgang and Figlio also traced the biographical and developmental records of all criminals in Philadelphia (Gregg, 2007).


Quantitative research methods are the best methods for use in studying criminal justice. They help in the collection, analysis and recording of criminal realities that can help deal with criminal cases. The commonest research types that may warrant the use of quantitative research methods include surveys, quasi-experimental research, experimental research, cross-sectional studies and longitudinal studies. Many of them also have branches that help carry out detailed researches. All these methods entail the use of samples in making didactic conclusions about the populations. Therefore, the samples must be fair and accurate. The application of these methods in criminal justice involves assigning numerical values to concepts of criminal justice for effective analysis of the results.


Gregg, B (2007). Battleground: Criminal justice. Westport, CT: Greenwood Press. Web.

Stringer, E., Agnello, M., Baldwin, S., Christensen, L., Henry, D., Henry, K.,… &Tinsley- Bateson, P. (1999). Community-based Ethnography: Breaking traditional boundaries of research, teaching and learning. British Educational Research Journal,25(4), 568-569. Web.

Dressler, J. (2002). Encyclopedia of Crime and Justice. New York: Macmillan Reference USA. Web.