_-Research Methods in Crime and Justice - Routledge

Research Methods in Crime and Justice
Chapter 7Variables and the Structure of Research
Variables and Hypotheses
In social science, we use variables to describe the different characteristics of individuals, groups, organizations and social phenomena.Themanner in which we describe things can sometimes help us understand a problem or phenomenon more precisely.
Variables and Hypotheses
Avariableis any characteristic of an individual, group, organization or social phenomenon that changes.Ahypothesisis a statement that predicts how a change in one or more variables will cause a change in another variable.
Types of Variables
Generally, there are three types of variables.Independent variablesDependent variablesIntervening variablesEach type of variable functions differently within a hypothesis.
Independent Variables
Anindependent variableis;the causal variable, orthe variable that a researcher predicts will be the cause of a change in another variable.
Dependent Variables
Adependent variableis;the effect, orthe variable that a researcher predicts will change as a result of a change in another variable or set of variables.
Independent vs. Dependent
An easy way to distinguish between the independent and dependent variables is to ask which happensfirst.Theindependent variable always happensfirst.The first causal rule (temporal order) requires that the cause (independent variable) must happen prior to the effect (dependent variable).
Independent or Dependent?
Children who experience domestic abuse are more likely as adults to abuse their domestic partners.Independent variable – Children who experience domestic abuse.Dependent variable – domestic abusive behavior as an adult.
Intervening Variables
Anintervening variableis any variable thatoccursbetween the independent and dependentvariables, andmay changehow, or even if, the independent variable affects a dependent variable.Inother words,intervening variablesintervenein thecausal relationship.
Independent, Dependent or Intervening?
Children who experience domestic abuse are more likely as adults to abuse their domestic partners, unless they develop strong attachments to non-abusive adults.Independent variable – Children who experience domestic abuse.Dependent variable – domestic abusive behavior as an adult.Intervening variable – strong attachments to non-abusive adults.
Variable Attributes
Attributesare the different characteristics or values that a variable can take on.A variable’s attributes must be both;ExhaustiveMutually exclusive
Exhaustiveness
Exhaustivenessrefers to the completeness of the list of attributes.Allof the possible attributes for each variable must be included.In some cases it may be necessary to include an ‘other’ in the list of attributes.
Mutual Exclusivity
Mutual exclusivityrequires that the list of attributes must bewe mean that each attribute must be distinctive, such that a respondent can pick one,and only one, option.
Elements of a Good Research Question
Aresearch questionis an interrogative statement.An actual questionNot a statementThere are four criteria of a good research question.MeasurableUnansweredFeasibleDisinteresting
Elements of a Good Research Question
Research questions should bemeasurable.The concepts in the question should be measurable, either quantitatively or qualitatively.Avoid the use of ambiguous terms and superlatives.Research questions should beunanswered.Most questions in the social sciences have been asked and answered by other researchers.This does not mean that we cannot ask them again or in different ways.
Elements of a Good Research Question
Research questions should befeasible.Money and time are always finite resources.Researchers should consider whether a particular research project is practical or feasible.Research questions should bedisinteresting.Researchers should be indifferent to the outcome of their research.Researchers never should try to prove anything, but be led by the evidence to the most logical conclusion.
Hypotheses in Social Research
Ahypothesisis a predictive statement that alleges a plausible connection between two or more variables.‘Predictive’ means the hypothesis makes a specific prediction about how two or more variables are connected.‘Plausible connection’ means that the hypothesis must describe the nature of the connection between the variables.All hypotheses contain two or more variables.
The Alternative Hypotheses
Analternative hypothesis (Ha)is a predictive statement alleging a plausible connection between two or more variables.This is the hypothesis the researcher wants to confirm as true at the end of the research.For each alternative hypothesis the researcher must develop a competing null hypothesis.
The Null Hypothesis
Anull hypothesis (Ho)is a predictive statement that alleges no plausible connection between two or more variables.The null hypothesis is the exact opposite of the alternative hypothesis.
Competing Hypotheses
Alternative hypothesis (Ha): Poor academic performance in the early elementary school years is positively related to juvenile delinquency in the adolescent years.Null hypothesis (Ho): Poor academic performance in the early elementary school years is not related to juvenile delinquency in the adolescent years.
The Structure of Research
In this research project the researcher wants to prove that the alternative hypothesis is a true statement.Before doing so, the researcher must first prove that the null hypothesis is a false statement.
The Structure of Research
If, the data lead the researcher to the conclusion that;Poor academic performance in the early elementary school years is not related to juvenile delinquency in the adolescent years (i.e. the null hypothesis).Then the researcher will accept the null hypothesis and reject the alternative hypothesis.
The Structure of Research
If on the other, hand the data lead the researcher to the conclusion that;Poor academic performance in the early elementary school years is not related to juvenile delinquency in the adolescent years (i.e. the null hypothesis).Is a false statement.Then, the researcher will reject the null hypothesis and accept the alternative hypothesis.
Why so Formal?
Why not just ignore the null hypothesis and try to prove the alternative hypothesis?Just as the criminal justice system must presume innocence, so, too, must a researcher presume no relationship between the variables in a research project.The formal structure of research is intended to insure the quality of research findings.
Other Types of Hypotheses
Separate from the distinction between the null and alternative hypotheses, a hypothesis can also be categorized into one of two types.A hypothesis of associationA hypothesis of differenceThis distinction is important because it determines how the researcher will analyze the data.
The Hypothesis of Association
Ahypothesis of associationalleges that a change in the independent variable(s) is associated with a change in the dependent variable.In most cases the independent variable in a hypothesis of association will be measured at the ordinal, interval or ratio level of measurement.Hence, the data used to test a hypothesis of association can be illustrated in a linear graph.
The Hypothesis of Difference
Ahypotheses of differencealleges that the independent variable(s) makes groups different with respect to the dependent variable.In most cases the independent variable in a hypothesis of difference will be measured at the nominal level of measurement.Hence, the data used to test a hypothesis of difference can be illustrated in a bar graph.
Getting to the Point
Avariableis any characteristic of an individual, group, organization or social phenomenon that changes.
Getting to the Point
Anindependent variableis the causal variable, or the variable that a researcher predicts will be the cause of a change in another variable.Adependent variableis the effect, or the variable that a researcher predicts will change as a result of a change in another variable or set of variables.
Getting to the Point
Anintervening variableis any variable that occurs between the independent and dependent variables, changing how, or even if, the independent variable affects a dependent variable.
Getting to the Point
Attributesare the different characteristics or values that a variable can take on.Exhaustivenessrefers to the completeness of the list of a variable’s attributes.Mutual exclusivity refers to the capacity for a list of attributes to provide one,and only one, option for each respondent
Getting to the Point
Good research questions should be;Measurable,Unanswered,Feasible, andDisinteresting.
Getting to the Point
Ahypothesis is a statement that predicts how a change in one or more variables will cause a change in another variable.Analternative hypothesisis a predictive statement that alleges a plausible connection between two or more variables.Anull hypothesisis a statement that alleges no plausible connection between two or more variables.
Getting to the Point
Ahypothesis of associationalleges that a change in the independent variable(s) is associated with a change in the dependent variable.If the independent variable is ordinal, interval or ratio, the hypothesis will be one of association.Hence, the data used to test a hypothesis of association can be illustrated in a linear graph.
Getting to the Point
Ahypothesis of differencealleges that the independent variable(s) makes groups different with respect to the dependent variable.If the independent variable is nominal, the hypothesis will be one of difference.Hence, the data used to test a hypothesis of difference can be illustrated in a bar graph.
Research Methods in Crime and Justice
Chapter 7Variables and the Structure of Research