This document discusses different types of quantitative research design, including correlational research, ex post facto research, experimental research, quasi-experimental research, single case research, and meta-analysis research. Correlational research examines relationships between two variables, while ex post facto research investigates possible cause-and-effect relationships by observing existing conditions retrospectively. Experimental research involves deliberately controlling and manipulating independent variables to observe their effects. Quasi-experimental research controls measurement factors but not exposure factors. Single case research assesses aspects of behavior over time through intervention effects. Meta-analysis aggregates results from multiple studies. Key terms discussed include correlation, variables, and ex post facto.

1. Quantitative Research
Design
Sarah Sinks

2. Quantitative Research:
• Systematic scientific investigation of data
and their relationships.

3. Overview of Qualitative research
• The objective of quantitative research is to
develop and employ mathematical models,
theories and hypotheses pertaining to
natural phenomena.
• Measuring is key in quantitative research
because it shows the relationship between
data and observation.

4. Correlational Research
• To find if the data has an observable
relationship that can be further specified
in terms of magnitude and/or an increase
or decrease.

5. Characteristics of Correlational
Research
• Correlation indicates the strength and
direction of a linear relationship between
variables.

6. Correlation and Significance
• Is there a relationship
between two
variables/data?
• What is the direction
of the relationship?
• What is the
magnitude?
• These relationships
may show any
tendency for the
variables to vary
consistently.
• Pearson’s product
moment coefficient
correlation: -1.0 to
+1.0

8. Ex post facto
‘from what is done afterwards’

9. • Studies that investigate possible cause
and effect relationships by observing an
existing condition or state of affairs and
searching back in time for plausible causal
factors.

10. Characteristics of Ex Post Facto
• Researcher takes the effect/dependent
variable and examines it retrospectively
• Establishes causes, relationships or
associations and their meanings.
• Researcher has little to no control over
independent variables.
• Flexible by nature.

11. When to use this?
• You can use this where more powerful
experimental designs are not possible;
when you are unable to select, control and
manipulate the factors necessary to study
cause and effect relationships directly, or
when control variables except a single
independent variable may be unrealistic
and artificial.

12. Ex post facto advantages and
disadvantages
Advantages
• Show a correlation where
more rigorous
experimentation is not
possible
• Exploratory tool
• Useful to avoid articiality
in the research.
• Shows cause and effect
relationships
Disadvantages
• Lack of control for
independent variable and
randomizing subjects.
• Never certain if causative
factor has been included
or identified
• Relationship between two
factors does not est.
cause and effect.
• May be regarded as too
flexible.

13. Experimental
• Research in which the investigator
deliberately controls and manipulates the
independent variable to observe the effect
of that change on another the dependent
variable.

14. How and when to use
Experimental Research
• Most commonly used in Educational
research.
• You vary the independent variable and
look for the effect it has on the dependent
variable.

15. How and When to use Quasi-
experimental research
• Used when you have control over the
“when and the whom of measurement”,
but lack control over the “when and to
whom of exposure.”
• Common in educational research.

16. How and when to use Single Case
research
• Process of continuous assessment of
some aspect of human behavior over a
period of time.
• Involves “intervention effects”, that are
replicated in the same subject(s) over
time.
• Used in many fields including psychology,
education and social work.

17. How and when to use Meta-
analysis research
• Research to explore the effectiveness of
classroom methods.
• Involves aggregating the results of other
studies into a coherent account.

18. Useful Terms
• Correlation- Indicates the strength and direction
of a linear relationship between two random
variables.
• Ex post facto- from the Latin for "from
something done afterward"
• Quasi- the prefix 'quasi' denotes methods that
are "almost" or "socially approximate"
• Variable- a measurable factor, characteristic, or
attribute of an individual or a system

19. References
• Research Methods in Education 5th
Edition, Louis Cohen, Lawrence, Manion
and Keith Morrison 2004, New York
• http://en.wikipedia.org/wiki/Main_Page,
4/10/2007