This document discusses different types of quantitative research designs: 1. Descriptive research involves exploring and describing phenomena without manipulating variables. It provides accurate characteristics of individuals, situations, or groups. 2. Correlational research investigates relationships between variables by measuring selected variables and determining their relationships using statistics. It can identify positive, negative, or no correlations. 3. Quasi-experimental research examines causal relationships by implementing an intervention or treatment and measuring its effects, with less control than experimental research. 4. Experimental research objectively and systematically predicts and controls phenomena by controlled manipulation of an independent variable, exposing subjects to treatment/control groups, and establishing cause-and-effect through random assignment.

1. UNIT 4 ( a) TYPES OF
QUANTITATIVE RESEARCH
Ms. Chanda Jabeen
Lecturer
RN, RM, BSN
M.Phil. Epidemiology & Public Health
PhD (Scholar) Epidemiology & Public Health
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2. Objectives
At the end of this presentation students will be
able
• To define research design
• To discuss the descriptive research design
• To describe the Correlational research design
• To discuss the Quasi-experimental design
• To explain the Experimental design
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3. Research Design
• A research design is a blueprint for conducting
a study.
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4. Types of Quantitative Research
Four common types of quantitative research
designs are included in this text:
• Descriptive
• Correlational
• Quasi-experimental
• Experimental
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5. • The type of quantitative research conducted
is influenced by the current knowledge of a
research problem. When little knowledge is
available, descriptive studies often are
conducted.
• As the knowledge level increases,
correlational, quasi-experimental, and
experimental studies are conducted.
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6. Descriptive Research
• Descriptive research is the exploration and
description of phenomena in real-life
situations. It provides an accurate account of
characteristics of particular individuals,
situations, or groups.
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7. • Descriptive studies are usually conducted with
large numbers of subjects or study participants,
in natural settings, with no manipulation of the
situation.
• Through descriptive studies, researchers
discover new meaning, describe what exists,
determine the frequency with which something
occurs, and categorize information in real-
world settings.
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8. • The outcomes of descriptive research include
the identification and description of concepts,
identification of possible relationships among
concepts, and development of hypotheses that
provide a basis for future quantitative
research.
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9. • Descriptive research is a study designed to
depict the participants in an accurate way.
More simply put, descriptive research is all
about describing people who take part in the
study. No manipulation of variables is
involved in a descriptive design.
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10. • There are three ways a researcher can go
about doing a descriptive research project,
and they are:
• Observational, defined as a method of
viewing and recording the participants
• Case study, defined as an in-depth study of
an individual or group of individuals
• Survey, defined as a brief interview or
discussion with an individual about a
specific topic
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11. Protection against bias in a descriptive design is
achieved through
(1) conceptual and operational definitions of
variables,
(2) sample selection and size,
(3) valid and reliable instruments, and
(4) data collection procedures that might
partially control the environment
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12. TYPES OF DESCRIPTIVE
RESEARCH DESIGNS
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13. 1. Typical Descriptive Design
A typical descriptive design is used to examine
variables in a single sample. This descriptive
design includes identifying the variables within a
phenomenon of interest, measuring these
variables, and describing them.
The description of the variables leads to an
interpretation of the theoretical meaning of the
findings and the development of possible
relationships or hypotheses that might guide
future correlational or quasi-experimental studies.
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15. 2. Comparative Descriptive Design
A comparative descriptive design is used to
describe variables and examine differences in
variables in two or more groups that occur
naturally in a setting.
A comparative descriptive design compares
descriptive data obtained from different groups,
which might have been formed using gender,
age, educational level, medical diagnosis, or
severity of illness.
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17. Correlational research
• Correlational research involves the
systematic investigation of relationships
between or among variables. When
conducting this type of study, researchers
measure selected variables in a sample and
then use correlational statistics to determine
the relationships among the study variables.
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18. • Using correlational analysis, the researcher is
able to determine the degree or strength and
type (positive or negative) of a relationship
between two variables. The strength of a
relationship varies, ranging from -1 (perfect
negative correlation) to +1 (perfect positive
correlation), with 0 indicating no relationship
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19. • There are three possible results of a
correlational study:
• a positive correlation,
• a negative correlation, and
• No correlation.
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20. • A positive relationship indicates that the
variables vary together; that is, both variables
increase or decrease together.
• For example, research has shown that the
more people smoke, the more lung damage
they experience.
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21. • A negative relationship indicates that the
variables vary in opposite directions; thus as
one variable increases, the other will decrease
• For example, research has shown as the
number of smoking pack-years (number of
years smoked times the number of packs
smoked per day) increases, people’s life
spans usually decrease, demonstrating a
negative relationship.
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23. • The strength of the relationship is measure of
how consistently the values of each variable
change in relation to each other. Graphically,
the stronger the relationship, the closer the
data points will fall along a line as seen in the
example below:
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26. TYPES OF CORRELATIONAL
RESEARCH DESIGNS
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28. Descriptive Correlational Design
The purpose of a descriptive correlational design
is to describe variables and examine
relationships among these variables.
Using this design facilitates the identification of
many interrelationships in a situation.
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30. Predictive Correlational Design
The purpose of a predictive correlational design
is to predict the value of one variable based on
the values obtained for another variable or
variables.
Prediction is one approach to examining
causal relationships between variables. Because
causal phenomena are being examined, the terms
dependent and independent are used to describe
the variables.
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32. Model Testing Design
The model testing design requires that all
concepts relevant to the model be measured and
the relationships among these concepts
examined.
A large heterogeneous sample is required.
Correlational analyses are conducted to
determine the relationships among the model
concepts, and the results are presented in the
framework model for the study.
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33. Quasi-Experimental Research
• The purpose of quasi-experimental research is to
examine causal relationships or determine the
effect of one variable on another. Thus these
studies involve implementing a treatment or
intervention and examining the effects of this
intervention using selected methods of
measurement.
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34. • In nursing research, a treatment is an intervention
implemented by researchers to improve the
outcomes of clinical practice.
• For example, a treatment of a swimming
exercise program might be implemented to
improve the balance and muscle strength of older
women with osteoarthritis.
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35. • Quasi-experimental studies differ from
experimental studies by the level of control
achieved by the researcher.
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36. Experimental research
• Experimental research is an objective,
systematic, highly controlled investigation
conducted for the purpose of predicting and
controlling phenomena in nursing practice.
• In an experimental study, causality between
the independent (treatment) and dependent
(outcome) variables is examined under highly
controlled conditions
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37. Characteristics of Experimental Research
The Four main characteristics of experimental
studies are the following:
(1) controlled manipulation of at least one
treatment variable (independent variable);
(2) exposure of some of the subjects to the
treatment (experimental group) and no exposure
of the remaining subjects (control group); and
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38. (3) Random assignment of subjects to the
control or experimental group.
4) Can establish cause and effect.
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39. • Random selection of subjects and the conduct
of the study in a laboratory or research facility
strengthen control in an experiment
• The degree of control achieved in
experimental studies varies according to the
population studied, variables examined, and
environment of the study.
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40. References
Burns, N. & Grove, S. K. (2007). Understanding
nursing research. (4th ed.).Philadelphia:W.B.
Saunders.
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