1. Educational Research:
Causal-Comparative Study
At least two different groups are compared on a
dependent variable or measure of performance
(called the “effect”) because the independent
variable (called the “cause”) has already occurred
or cannot be manipulated.
Dependent variable-the change or difference
occurring as a result of the independent variable.
Independent variable- an activity of characteristic
believed to make a difference with respect to some
behavior.
2. Purpose of causal comparative
research
The researcher attempts to determine the cause,
or reason, for pre existing differences in groups
of individuals.
Attempts to identify cause and effect
relationships.
Involve two or more group variables.
Involve making comparison.
Individuals are not randomly selected and
assigned to two or more groups.
Cannot manipulate the independent variable
Less costly and time consuming
4. Example: The Relationship between Years of
Experience and Job Satisfaction
Causal Comparative Design
Hypotheses
• Alternative- Teachers with a high level of experience
will be more satisfied with their jobs than teachers with
low levels of experience.
• Null- Teachers with a high level of experience will be
equally satisfied with their jobs when compared to
teachers with low levels of experience.
Variables
• Dependent- Job satisfaction
• Independent- Years of experience
• Two levels (high & low)
• Exists naturally in the population of teachers at the
start of study.
5. Sample
Two groups sampled, one for each level of the independent
variable:
• High Experience
• Low Experience
Select two groups that differ on some independent variable
• One group possesses some characteristic that the other does not
• Each group possesses the characteristic but in differing amount
• The independent variable must be clearly operationally defined
• * Randomly sample subjects from each of the two groups
• Collect background information on subjects to determine the
equality of the groups
• Compare groups on the dependent variable
6. Control of Extraneous variable
What other variable besides years of experience could
explain job satisfaction among teachers?
Matching: Each subject in the high experience group
is matched with a subject with a low experience group
along the variable of class size.
Each high experience teacher who teachers a large
class is matched with a low experience teacher who
teaches a large class.
Each high experience teacher who teaches a small
class is matched with a low experience teacher who
teaches a small class.
7. Data Analysis
• Mean - job satisfaction ratings for High Experience and Low
Experience subjects are compared using t-test, ANOVA or
other appropriate statistical test.
• Rejection of the null hypothesis supports the alternative
hypothesis that years of experience result in increased job
satisfaction.
8. Example of Research Objectives
To identify the purpose of of Causal
Comparative Research?
To Identify the meaning of Causal
Comparative Research topics and describe
the basic design?
To examine the type of Causal Comparative
Research?
9. Example of Research Questions :
1. What are the strengths of the study?
Groups are comparable to one another.
Contrasted statistical with practical significance.
Large sample size.
Multiple “replications” of treatment effect.
2. What are the weaknesses of the study?
Lack of random assignment.
Focus on standardized test performance.