The document discusses research design. It defines research design as a blueprint that outlines how, where, and on whom a research study will be conducted. Experimental research design specifically examines the effect of independent variables on dependent variables by manipulating the independent variable. True experimental designs allow researchers to control extraneous variables and isolate the effect of the independent variable on the dependent variable. Several true experimental designs are described including post-test only, pretest-posttest, Solomon four-group, factorial, randomized block, and crossover designs.

2. INTRODUCTION
 Research design is the framework or guide
used for the planning, implementation, and
analysis of a study.
 It is a systematic plan of what is to be done,
how it will be done, and how the data will be
analysed.
 Experimentation is the most scientifically
sophisticated research method.
 It is observation under controlled conditions.
 In experimental design researcher is an active
agent rather than passive observer.

3. DEFINITION
 Research design: It can be defined as a blue print of
research study, which enables the researcher to know on
whom, what, when, where, and how the study will be
conducted.
 Experimental research design: Experimental research
designs are concerned with examination of the effect of
independent variable on the dependent variable, where the
independent variable is manipulated through treatment or
intervention(s), and the effect of these interventions is
observed on the dependent variable.
Or
 According to Riley, experimental research design is a
powerful design for testing hypotheses of causal relationship
among variables.

4. ELEMENTS OF RESEARCH
DESIGN
 Qualitative Research design includes the five
major elements. These are:
Elements of
research design
Tools & method(s) of
data collection
Time and place of
data collection
The approach
Method of data analysis
Population, sample and
sampling technique
Qualitative
Quantitative
Or both
With/without
conceptual
framework

5. SELECTION OF RESEARCH
DESIGN
 Research designs are plans and the
procedures for research. To meet the aims and
objectives of a study, researchers must select
the most appropriate design.

6.  Factors affecting selection of research
design
Nature and purpose of the research
problem
Researcher's knowledge and experience,
interest and motivation
Research ethics and principles
Subjects/participants
Resources and time

7. TYPES OF RESEARCH DESIGN
Research designs are classified into two broad
categories and several subtypes.
 Quantitative research designs
 Qualitative research designs

8. A. QUANTITATIVE RESEARCH DESIGNS
Types of research designBroad categories
1. Experimental research design True experimental design
Post-test-only control design
Pre-test-posttest control group design
Solomon four-group design
Factorial design
Randomized block design
Crossover design
Quasi experimental design
 Nonrandomized control group design
 Time-series design
Pre-experimental design
 One-shot case design
 One-group pretest-post-test design
TYPES OF RESEARCH DESIGN

9. 1. Non-experimental research designs a. Descriptive design
 Univarent descriptive design
 Exploratory descriptive design
 Comparative descriptive design
b. Correlational/ex post facto design
 Prospective design
 Retrospective design
c. Developmental research design
 Cross-sectional design
 Longitudinal design
d. Epidemiological designs
 Case-control studies
 Cohort studies
e. Survey research design
A. QUALITATIVE RESEARCH DESIGN a. Phenomenological research
b. Ethnographic research
c. Grounded theory
d. Case studies
e. Historical research
e. Action research

10. TRUE EXPERIMENTAL DESIGNS
 The true research design are those where
researchers have complete control over the
extraneous variables and can predict
confidently that the observed effect on the
dependent variable is only due to the
manipulation of the independent variable.

11. Main characteristics
 Manipulation: it refers to conscious control of the
independent variable by the researcher through
treatment or intervention(s) to observe its effect on
dependent variable.
 Control: it refers to the use of control group and
controlling the effects of extraneous variable in which
researcher is interested.
 Randomization: it means that every subject has and
equal chance of being assigned to experimental or
control group. Randomization is used in true
experimental research designs to minimize the threat
of internal validity of the study and to eliminate the
effect of extraneous variables on dependent variable.

12. Types of True Experimental Designs
 Post test only
 Pretest post-test only
 Soloman 4 groups
 Factorial design
 Randomized block design
 Cross over design

13. Post test only control design:
composed of two randomly assigned groups, i.e.
experimental and control but neither of which is
pretested before the administration of treatment on
the experimental group.
For example, to study the effect of an educational
intervention related to urinary incontinence on the
subsequent help seeking behaviour of older adults.
Experimental
group Treatment Post-test
Control
group Post-test
Random
assignment

14. Pretest post-test only: subjects are randomly
assigned to either the experimental or control
group.
 The effect of the dependent variable on both
the groups is seen before the treatment.
 Later the treatment is carried out on
experimental group only, and after treatment
observation of dependent variable is made on
both the groups to examine the effect of the
manipulation of independent variable on the
dependent variable.

15.  For example, such a design can be used for
‘an experimental study to assess the
effectiveness of cognitive behavioural therapy
interventions for patients with breast cancer.’
Experimental
group
Pretest Treatment Post-test
Control group Pretest Post-test
Random
assignment

16. Soloman 4 group design: there are two experimental
groups (experimental group 1 and experimental group
2) and two control groups (control group 1 and control
group 2).
 The investigator randomly assigns subjects to four
groups. Out of the four groups, only experimental
group 1 and control group 1 receives the pretest,
followed by the treatment to the experimental group 1
and experimental group 2.
 Finally, all the four groups receive post-test, where
the effects of the dependent variables of the study are
observed and comparison is made of the four groups
to assess the effect of independent variable on
dependent variable.

17.  The soloman four group design is believed to be
the most prestigious experimental research
design because it minimizes the threat to
internal and external validity.
Exp group 1 Treatment Post-test
Control group 1 Post-test
Exp group 2 Treatment Post-test
Control group 2 Post-test
Random
assignment
Pretest
Pretest

18. Factorial design: the researcher manipulates two
or more independent variables simultaneously
to observe their effects on the dependent
variables.
 This design is useful when there are more
than two independent variables, called factors
to be tested.
 For example, a researcher wants to observe
the effects of two different protocols of mouth
care prevention of VAP when performed at
different frequencies in a day.

19. Frequency of mouth
care
Protocols of mouth care
Chlorohexidine(α1) Saline (α2)
4 hourly(β1) (α1) ..(β1) (α2) ..(β1)
6 hourly(β2) (α1) ..(β2) (α2) ..(β2)
8 hourly(β3) (α1) ..(β3) (α2) ..(β3)
 This design also facilitates the testing of several
hypothesis at a single time. Typical factorial
design incorporates 2x2 or 2x3 factorial, but it can
be any combination. The first number (α) refers to
the independent variables or the types of
experimental treatments, and the second number
(β) refers to the level or frequency of the
treatment.

20. Randomized block design: when there are large
number of experimental comparison groups, the
randomized block design is used to bring
homogeneity among selected different groups.
 This design looks similar to factorial design in
structure, but out of two factors, one factor is not
experimentally manipulated.
 For example, a researcher wants to examine the
effects of three different types of antihypertensive
drugs on patients with hypertension. To ensure
the homogeneity among the subjects under
treatment, researcher randomly places the
subjects in homogeneous groups (blocks).

21. Types of
antihypertensive
drugs
Blocks
Pts. With primary
hypertension (I)
Diabetic pts. With
hypertension (II)
Renal pts. With
hypertension (III)
A A, I A, II A, III
B B, I B, II B, III
C C, I C, II C, III
 There are two factors: type of antihypertensive
drugs and type of patients with hypertension,
where only the type of drug is manipulated and
types of patients with hypertension are simply
grouped in different blocks with similar
characteristics to ensure homogeneity.

22. Cross over design: in this design, subjects are
exposed to more than one treatment, where
subjects are randomly assigned to different
orders of treatment. It is also known as ‘repeat
measures design’.
 For example, when we are comparing the
effectiveness of chlorohexidine and saline
mouth care protocol, first we administer the
chlorohexidine mouth care protocol on group 1
and saline mouth care protocol on subjects of
group 2.

23. Groups PROTOCOLS OF MOUTH CARE
Group I chlorohexidine(α1) saline(α2)
Group I saline(α2) chlorohexidine(α1)
 Later the treatment is swapped where group 1
receives saline mouth care and group 2
receives chlorohexidine. In such studies,
subjects serve their own control.

24. Advantages
 Considered most powerful
designs
 Greater degree of purity
 Conditions not found in
natural setting can be
created in experimental
setting
 Conditions can be created
in short period of time that
may take years to occur
naturally
Disadvantages
 Ethical problems
 Many of human variables
neither have valid
measurable criteria nor
instruments to measure
them.
 Not possible to impose
control over extraneous
variables in natural
settings
 Difficult to get cooperation
from study subjects