Rsearch design

Research Design
• Decisions regarding what, where, when,
how much
• A major issue in research is the preparation
of the research design of the research
project Decisions regarding what, where,
when, how much, by what means,
concerning an enquiry or a research study
constitute a research design

Research Design – Definition

• “A research design is the arrangement of
conditions for collection and analysis of data
in a manner that aims to combine relevance to
the research purpose with economy in
procedure”
• Is the conceptual structure within which
research is conducted; it constitutes the
blueprint for the collection, measurement and
analysis of data

Research Design…
More explicitly:
• What is the study about?
• Why is the study being conducted?
• Where will the study be carried out?
• What type of data is required?
• Where can the required data be found?
• What period of time will the study include?
• What will be the sample design?
• What techniques of data collection will used?
• How will the data be analyzed?
• In what style will the report be prepared?

Research Design has the following
parts:
Split the overall research design into the following parts:
• (a) sampling design
– the method of selecting items to be observed;
• (b) observational design
– the conditions under which the observations are to be made;
• (c) statistical design
– the question of how many items are to be observed and how
the information and data gathered are to be analysed;
• (d) operational design
– the techniques by which the procedures specified in the
sampling, statistical and observational designs can be
carried out.

• The important features of a research design
– (i) a plan
• specifies the sources & types of information
relevant to the research problem
– (ii) a strategy
• which approach will be used for gathering and
analyzing the data.
– (iii) the time and cost budgets
• most studies are done under these two
constraints

In brief, a research design
must contain:
• A clear statement of the
research problem
• Procedures and techniques to
be used for gathering
information
• The population to be studied
• Methods to be used in
processing and analyzing
data

NEED FOR RESEARCH DESIGN
• Research Design is needed because it facilitates the smooth sailing
of the various research operations, thereby making research as
efficient as possible yielding maximal information with minimal
expenditure of effort, time and money.
• Just as for better, economical and attractive construction of a
house, we need a blueprint( or what is the commonly called the
map of the house) well thought out and prepared by an expert
architect, similarly we need a research design or a plan in advance
of data collection and analysis for our research project.
• Research design stands for advance planning of the methods to be
adopted for collecting the relevant data and the techniques to be
used in their analysis, keeping in view the objective of the
research and the availability of staff, time and money.

FEATURES OF A GOOD DESIGN
A research design appropriate for a particular
research problem, usually involves the following
features.
• The mean of obtaining information.
• The availability and skills of the researcher and
his staff, if any.
• The objective of the problem to be studied.
• The nature of the problem to be studied .
• The availability of time and money for the
research work.

Research Design – Important
Concepts
• Dependent and Independent Variables
• Extraneous Variable
• Control
• Confounded Relationship
• Research Hypothesis
• Experimental and
• Non-experimental Hypothesis-testing

Dependent & Independent Variables
– A concept which can take on different quantitative
values (a variable)
– Qualitative phenomena (or the attributes) are also
quantified
– If one variable depends upon or is a consequence
of the other variable --- a dependent variable,
– the variable that is antecedent to the dependent
variable --- an independent variable.

Extraneous Variable
– Independent variables that are not related to the purpose of the
study, but may affect the dependent variable
• the researcher wants to test the hypothesis: a relationship
between children’s gains in social studies achievement and
their self-concepts
– self-concept is an independent variable, social studies
achievement is a dependent variable.
– Intelligence may as well affect the social studies
achievement, but since it is not related to the purpose of
the study undertaken by the researcher, it will be termed
as an extraneous variable.
– Whatever effect is noticed on dependent variable as a result of
extraneous variable(s) is technically described as an
‘experimental error’.

Control

• One important characteristic of a good
research design is to minimize the influence or
effect of the EV. The term “Control” is used
when we design the study minimizing the
effects of extraneous variables.

Confounded Relationship
– When the dependent variable is not free
from the influence of extraneous variable(s)
– the relationship between the dependent and
independent variables is said to be
confounded/confused by an extraneous
variable(s).

Research Hypothesis

– When a prediction or a hypothesized
relationship is to be tested by scientific
methods, it is termed as research
hypothesis.
– The research hypothesis is a predictive
statement that relates an independent
variable to a dependent variable.

Experimental and Non-Experimental
Hypothesis testing research
– When the purpose of research is to test a research
hypothesis, it is termed as hypothesis-testing
research.
– It can be of the experimental design or of the non-
experimental design.
• For instance, a researcher wants to study whether
intelligence affects reading ability for a group of students
and for this purpose he randomly selects 50 students and
tests their intelligence and reading ability by calculating the
coefficient of correlation between the two sets of scores.

Experimental and control groups

– An experimental hypothesis-testing research
when a group is exposed to usual conditions,
it is termed a ‘control group’, but when the
group is exposed to some novel or special
condition, it is termed an ‘experimental
group’.

Treatments
– The two treatments are the usual studies
programme and the special studies programme
• For example, if we want to determine through an
experiment the comparative impact of three varieties
of fertilizers on the yield of wheat, in that case the
three varieties of fertilizers will be treated as three
treatments.

Experiment
– Examining the truth of a statistical hypothesis, relating to
some research problem, is known as an experiment.
• For example, an experiment to examine the usefulness of a
certain newly developed drug
– Experiments can be of two types viz., absolute experiment
and comparative experiment.
• If we want to determine the impact of a fertilizer on the
yield of a crop, it is a case of absolute experiment;
• but if we want to determine the impact of one fertilizer as
compared to the impact of some other fertilizer, our
experiment then will be termed as a comparative
experiment.

Experimental unit(s)
– The pre-determined plots or the blocks,
where different treatments are used, are
known as experimental units.
– Such experimental units must be selected
(defined) very carefully.

DIFFERENT RESEARCH DESIGNS

• Different research designs can be conveniently
described if we categorize them as:
• (1) research design in case of exploratory research
studies;
• (2) research design in case of descriptive and
diagnostic research studies, and
• (3) research design in case of hypothesis-testing
research studies.

Research design in case of
exploratory research studies
– also termed as Formulative research studies
– The main purpose
• formulating a problem for more precise investigation
• of developing the working hypotheses from an
operational point of view
• The major emphasis is on the discovery of ideas and
insights

Exploratory Research
Design…

The following 3 methods are used:
• The survey concerning literature
• The experience survey
• The analysis of “insight-stimulating”
examples

The Literature Survey
• The most simple and useful method of
formulating the research problem or
developing a hypothesis
• Hypotheses stated by earlier workers
may be reviewed and their usefulness
evaluated as a basis for further
research
• Use the bibliographical survey of
studies already done in one’s area of
interest for formulating the problem
• An attempt must be made to apply
concepts and theories

Experience Survey
– Is the survey of people who have had
practical experience with the problem
– The object is to obtain insight into
relationships between variables and new
ideas relating to the research problem

Analysis of ‘insight-stimulating’
examples
– The method consists of the intensive
study of selected instances of the
phenomenon in which one is
interested
– For this purpose, existing records
may be examined; unstructured
interviews with experts may be
conducted; etc.

Research design in case of descriptive
and diagnostic research studies
• Descriptive Studies are those which are concerned with describing
the characteristics of a particular individual or of a group.
• Studies concerned with specific predictions, with narration of facts
and characteristics concerning individual, group or situation are
ex.'s of descriptive research studies
• Diagnostic Studies determine the frequency with which something
occurs or its association with something else
• Studies about whether certain variables are associated, are ex.’s of
diagnostic studies
– The research design here must focus on the following:
» Formulating the objective of the study
» Designing the methods of data collection
» Selecting the sample
» Collecting the data
» Processing and analyzing the data
» Reporting the findings

Type of study
Research Design
Exploratory of Formulative Descriptive/Diagnostic

Flexible design (design must Rigid design (design must
Overall design provide opportunity for considering make enough provision for
different aspects of the problem) protection against bias and
must maximize reliability)

(i) Sampling design Non-probability sampling design Probability sampling design
(purposive or judgment sampling) (random sampling)

(ii) Statistical design No pre-planned design for analysis Pre-planned design for
analysis
(iii) Observational design Unstructured instruments for Structured or well thought out
collection of data instruments for collection of
data
(iv) Operational design No fixed decisions about the Advanced decisions about
operational procedures operational procedures.

Research design in case of
hypothesis-testing research studies

• Hypothesis-testing research studies (generally known as
experimental studies) are those where the researcher tests the
hypotheses of causal relationships between variables. Such
studies require procedures that will not only reduce bias and
increase reliability, but will permit drawing inferences about
causality.
• Usually experiments meet this requirement. Hence, when we
talk of research design in such studies, we often mean the
design of experiments.

BASIC PRINCIPLES OF
EXPERIMENTAL DESIGNS

The three important principles are:
• Principle of Replication
• Principle of Randomization
• Principle of Local control

Principle of Replication
• The experiment should be repeated more than
once to ensure that each treatment is applied
in many experimental units instead of one.
• By doing so the statistical accuracy is
increased

Principle of Randomization
• Provides protection against the effect of
extraneous factors in an experiment.
• That is, we design the experiment in such a way
that the variations caused by extraneous factors
can all be combined under the general heading
of “chance”.
• Design or plan the experiment that the variations caused
by extraneous factors
• The principle of randomization, have a better estimate of
the experimental error.

Principle of Local Control
• Here the extraneous factor, the known source of
variability, is made to vary deliberately over as wide
a range as necessary and this needs to be done in such
a way that the variability it causes can be measured
and hence eliminated from the experimental error.

Important Experimental Designs
There are several designs:
 Informal Experimental Designs
 Formal Experimental Designs
 Informal Experimental Designs
Before-and-after without control design
After-only with control design
Before-and-after with control design
 Formal Experimental Designs
Completely Randomized design
Randomized block design
Latin Square design
Factorial design

Informal Experimental
Designs
• Before-and-after without control design: = level
of phenomenon after the treatment-level of
phenomenon before the treatment.
• After-only with control design: value of
dependent variable in the test area-value of
dependent variable in the controlled area.
• Before-and-after with control design: change in
dependent variable in the test area-change in
dependent variable in the controlled area.

Before-and-after without control
design
• In such a design a single test group or area is
selected and the dependent variable is measured
before the introduction of the treatment. The
treatment
• is then introduced and the dependent variable is
measured again after the treatment has been
introduced. The effect of the treatment would be
equal to the level of the phenomenon after the
treatment minus the level of the phenomenon
before the treatment.

• The design can be represented thus:

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After-only with control design
• In this design two groups or areas (test area and control
area)are selected and the treatment is introduced into the
test area only. The dependent variable is then measured
in both the areas at the same time. Treatment impact is
assessed by subtracting the value of the dependent
variable in the control area from its value in the test area.
• Two groups or areas (test area and control area) are
selected and the treatment is introduced into the test
area only

Before-and-after with control design

• In this design two areas are selected and the dependent
variable is measured in both the areas for an identical
time-period before the treatment. The treatment is then
introduced into the test area only, and the dependent
variable is measured in both for an identical time-period
after the introduction of the treatment. The treatment
effect is determined by subtracting the change in the
dependent variable in the control area from the change
in the dependent variable in test area.

Before-and-after with control design

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Completely randomized design
(C.R. design)
• Involves only two principles viz., the principle of replication
and the principle of randomization of experimental designs. It
is the simplest possible design and its procedure of analysis is
also easier. The essential characteristic of the design is that
subjects are randomly assigned to experimental treatments (or
vice-versa).
• Two-group simple randomized design
– In a two-group simple randomized design, first of all the population
is defined and then from the population a sample is selected
randomly.(Refer Book: Fig. 3.4:Two-group simple randomized
experimental design (in diagram form)
• Random replications design
– The limitation of the two-group randomized design is usually
– eliminated within the random replications design(Refer Book: Fig.
3.5:Random replication design (in diagram form))

Completely randomized design (C.R.
design)
– (i) Two-group simple randomized design

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Randomized block design
(R.B.design)
• Randomized block design (R.B. design) is an
improvement over the C.R. design
• In the R.B.design the principle of local control can be
applied along with the other two principles of
experimental designs
• The main feature of the R.B. design is that in this each
treatment appears the same number of times in each block.
• The R.B. design is analysed by the two-way analysis of
variance (two-way ANOVA)* technique.

Random replications design

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Randomized block design (R.B. design)

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Latin square design (L.S. design)
• Latin square design (L.S. design) is an experimental
design very frequently used in agricultural research. The
conditions under which agricultural investigations are
carried out are different from those in other studies for
nature plays an important role in agriculture.

Factorial designs
• Factorial designs are used in experiments where the effects of varying more
than one factor are to be determined. They are specially important in several
economic and social phenomena where usually a large number of factors
affect a particular problem.
• Factorial design scan be of two types:
– (i) simple factorial designs and
– (ii) complex factorial designs.
• We take them separately
• (i) Simple factorial designs: In case of simple factorial designs, we
consider the effects of varying two factors on the dependent variable, but
when an experiment is done with more than two factors, we use complex
factorial designs. Simple factorial design is also termed as a ‘two-
factor-factorial design’, whereas complex factorial design is
known as ‘multi-factor-factorial design.’
• (i) Complex factorial designs: Experiments with more than two factors at a
time involve the use of complex factorial designs. A design which considers
three or more independent variables simultaneously is called a complex
factorial design

Factorial designs are used mainly because
of the two advantages
– (i) provide equivalent accuracy
• determine the main effects of two (in simple
factorial design) or more (in case of complex
factorial design) factors (or variables) in one
single experiment.
– (ii) permit various other comparisons of
interest

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Conclusion
• There are several research designs and
the researcher must decide in advance of
collection and analysis of data as to
which design would prove to be more
appropriate for his research project. He
must give due weight to various points
such as the type of universe and its
nature, the objective of his study, the
resource list or the sampling frame,
desired standard of accuracy and the like
when taking a decision in respect of the
design for his research project.

Rsearch design

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