Non Experimental research design in details.ppt

774 views 54 slides Aug 08, 2024
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About This Presentation

Nonexperimental research design is one of the broad categories of the research designs in which the researcher observes the phenomena as they occur naturally & no external variables are introduced.
it is a research design in which neither the variables are deliberately manipulated nor is the...


Slide Content

Prepared by:- Mr. Abhinav Bhatt

INTRODUCTION…
Nonexperimental research design is one of the
broad categories of research designs, in which the
researcher observes the phenomena as they occur
naturally, & no external variables are introduced.
It is a research design in which variables are not
deliberately manipulated, nor is the setting
controlled.
In nonexperimental research, researchers collect
data without making changes or introducing
treatments.

Data in nonexperimental research are generally
collected through the use of questionnaires,
interviews, observations, literature reviews &
critical-incidence technique.

NEED OF NONEXPERIMENTAL DESIGN
Nonexperimental designs can be used to conduct a
study are as follows:
The studies in which the independent variables
cannot be maintained.
The studies in which it is unethical to manipulate
the independent variable, i.e. manipulation may
cause physical or psychological harm to subjects.
The studies or research situations where it is not
practically possible to conduct experiments.
Descriptive-type studies that do not require any
experimental approaches.

TYPES OF NONEXPERIMENTAL RESEARCH
DESIGN
Descriptive Design
Univariant descriptive design
Exploratory descriptive design
Comparative descriptive design
Correlational design
Prospective design
Retrospective design
Developmental Research Design
Cross-sectional design
Longitudinal design
Epidem
iological Design
Case-control studies
Cohort studies
Survey Research Design

DESCRIPTIVE
RESEARCH
DESIGN

INTRODUCTION…
The purpose of descriptive studies is to
observe, describe, & document aspects of
a situation as it naturally occurs, &
sometimes to serve as a starting point for
hypothesis generation or theory
development.
Its utilized by researcher to determine the
extend or directions of attitude or
behaviours.

MAIN FEATURES…
Descriptive designs are used to observe,
document, & describe a phenomenon occurring
in its natural setting without any manipulation
or control.
The descriptive studies are designed to gain
more information about characteristics within a
particular field in the real world.
Descriptive studies provide an impression of a
situation as it occurs in natural settings.
Descriptive studies do not involve the
manipulation of variables, & variables are
studies as they exist in the real world.

Count…
Descriptive design may be used to develop
theories, identify problems with current practices,
justify current practices, make judgments, or
determine other practices in similar situations.
In descriptive studies, bias is prevented through
operational definitions of variables, large sample
size, random sampling techniques, valid & reliable
research tools, & formal data collection methods.
Descriptive designs include identification of
phenomenon of interest, identifying the variables
within the phenomenon, developing operational
definitions of the variables, & describing the
variables.

TYPES OF DESCRIPTIVE DESIGN
1.Univariant descriptive design
2.Exploratory design
3.Comparative design

1.Univariant descriptive design
Univariant descriptive designs are undertaken to
describe the frequency of occurrence of a phenomenon.
This design does not necessarily focus on the study of a
single variable; there may be one or more variables
involved in the study.
For example, a researcher is interested in assessing the
experiences of patients suffering from rheumatoid
arthritis. In this study, the researcher may describe the
frequency of different symptoms experienced by the
patients & the type of treatment they received during
the course of disease, etc. There are multiple variables
in this research study.

2.Exploratory design:
Exploratory design is used to identify, explore, &
describe the existing phenomenon & its related
factors.
In other words, it is not only a simple description
or the frequency of occurrence of a phenomenon,
but its in-depth exploration & a study of its related
factors to improve further understanding about a
less-understood phenomenon.
For example, an exploratory study to assess the
multifactorial dimensions of falls & home safety
measures for elderly people living in selected
communities in the city Mehsana.

3.Comparative design:
Comparative design involves comparing &
contrasting two or more samples of study
subjects on one or more variables, often at a
single point of time.
This design is used to compare two distinct
groups on the basis of selected attributed such
as knowledge level, perceptions, & attitudes;
physical or psychological symptoms; & so on.
For example, ‘A comparative study on health
problems among rural & urban older people in
district Mehsana, Gujarat.

CORRELATIONAL
RESEARCH
DESIGN

INTRODUCTION…
This is a nonexperimental design, where
researcher examines the relationship between
two or more variables in a natural setting
without manipulation or control.
In other words, it is a research design where
researchers study the relationship of two or
more variables without any intervention.
For example, this design was used for ‘A
correlational study on the effect of smoking on
lung cancer among people in Mehsana.

MAIN FEATURES…
In correlational studies, the researchers
examine the strength of relationships
between variables by determining how
change in one variable is correlated with
change in the other variable.
Generally, correlational studies have
independent & dependent variables, but
the effect of independent variable is
observed on dependant variable without
manipulating the independent variable.

Count…
In some correlational studies, identification of the
independent & dependent variables is difficult; however,
in most correlational studies, the independent variable is
identified, which, without any intervention, influences the
dependent variable. For example, this design was used in
‘a correlational investigation of the study habits & visual
acuity among school children studying in selected schools
in the city of Mehsana’.
In this study, study habits are the
independent variable, while visual acuity is the dependent
variable.
In epidemiological language these studies are known as
cause & effect study, where cause & effect relationship is
investigate in natural settings without imposing
experimental interventions. This cause & effect
relationship can be investigated either in forward
manner, i.e. from cause to effect (prospective) or
backward manner, i.e. effect to cause (retrospective)

TYPES OF CORRELATIONAL
RESEARCH DESIGN
1.Prospective research design
2.Retrospective research design

1.Prospective research design:
A design in which the researcher relates the
present to the future is a prospective
research design .
Prospective studies start with a presumed
cause & then go to presumed effects.
In this research design , researcher observes
phenomenon from cause to effect.
Prospective designs are often longitudinal,
but may also be cross sectional.

Count…
for example, a researcher conducting ‘a
prospective correlational study on effect of maternal
infection during pregnancy on foetal development &
pregnancy outcome .’
In this study, the researcher starts by collecting data
from pregnant women regarding any history of
infection among women during their current
pregnancies, next observes foetal development &
pregnancy outcome, & finally analyses the
relationship of maternal infection during pregnancy
& foetal development & pregnancy outcome.

2.Retrospective research design:
A design in which the researcher studies the
current phenomenon by seeking information
from past is a retrospective research design.
In this the researcher links the present
phenomenon with the past events.
In other words, the researcher has a
backward approach to study a phenomenon,
where he or she moves from effect to identify
the cause.

Count…
For example, this design was used in ‘a
retrospective correlational study on
substance-abuse-related high-risk factors
among traumatic head injury patients
admitted in neurosurgery ICU of Civil
Hospital, Gandhinagar.
In this study, the researcher first approached
head injury patients, & then tried to identify
the number of head injuries that occurred
under the influence of substance abuse.

DEVELOPMENTAL
RESEARCH
DESIGN

INTRODUCTION…
Developmental research design examines the
phenomenon with reference to time.
Developmental research designs are generally
used as adjunct research designs with other
research designs such as cross-sectional-
descriptive, longitudinal-correlational research
designs.

TYPES OF DEVELOPMENTAL
RESEARCH DESIGN
1.Cross-sectional design
2.Longitudinal design

1.Cross-sectional design:
Cross-sectional research design is one in which
researcher collects data at particular point of
time (one period of data collection).
These studies are easier & more convenient to
carry out.
For example, a researcher is interested in
assessing the awareness on swine flu among
people of an area.
Here the researcher interacts only once to collect
awareness-related data from respondents.

2.Longitudinal design:
Longitudinal research design is used to collect data over
an extended time period (long-time study).
Its value is in its ability to demonstrate change over a
period of time.
For example, a researcher in interested in the perception
of nursing students towards nursing profession from the
beginning of nursing programme to its end.
In this example, it is appropriate to use the longitudinal
research design to study this phenomenon.
Longitudinal studies are generally classified into three
types:
I.Trend studies
II.Panel studies
III.Follow-up studies

Count…
I.Trend studies:
These help to investigate a sample
from a general population over a time
with respect to some phenomenon.
Trend studies permit researchers to
examine pattern & rate of changes &
to make prediction about future
direction based on previously
identified patterns & rates of changes.

Count…
II.Panel studies:
A panel in research is referred to the sample
of people involved in a study.
In panel studies, same people are involved &
over a period of time they become more
informative on the phenomenon than the
subjects in trends studies because the
researcher can not only examine the patterns
of change, & but also the reasons for change.
The same selected people are contacted for
two or more times to collect further data.

Count…
III.Follow-up studies:
These are undertaken to determine
the subsequent states of subject(s)
with a specific condition or those who
have received a specific intervention.

EPIDEMIOLOGICAL
RESEARCH
DESIGN

CONCEPT…
Epidemiology is the study to investigate the
distribution & causes of the diseases in
population.
Therefore, epidemiological studies are
generally conducted to investigate causes of
different diseases in either prospective
approaches (causes to effect) or retrospective
designs.
Prospective studies are known as cohort
studies & retrospective studies are called case-
control studies.

Count…
(a) Cohort studies:
Called analytical (observational/ prospective) study.
In this design, a longitudinal approach is used to
investigate the occurrence of a disease in existing
presumed causes (suspected).
For example, a researcher longitudinally observes the
smokers for development of lung cancer. 
Feature:-
The cohorts are identified prior to the appearance of the
disease under investigation.
The study groups, so defined, are observed over a period
of time to determine the frequency of disease among them.
The study proceeds forward from cause to effect.

A Cohort is a specific group of people, at a certain
time, sharing common characteristics or
experience e.g. people born on the same day or
the same year (birth cohort), couple married in
the same year (marriage cohort), class of
nursing students (experience cohort), people
with same occupation (occupation cohort) etc.
 cohort studies can be designed in three
different ways, these are:
a)Prospective cohort
b)Retrospective cohort
c)A combination of retrospective and prospective
cohort

a. Prospective cohort study
Cohort study is prospective in nature because
the group under study is free from the disease
but exposed to risk factor and epidemiologist
study the development of a condition over time.
In this method of study the epidemiologist
selects a cohort i.e. a group of people say in the
same age group and who are exposed to risk
factor say “cigarette smoking (study group) and
a group of people in the same age group and
other similar characteristics but not exposed to
the risk factors (control group).

Both the groups are followed up for several
years and observation are made with
reference to frequency and distribution of the
suspected disease (in this example-lung
cancer) over a period of time. The data is
statistically analysed and comparisons are
done between the incidence among smokers
and non-smokers to determine the association
of risk factors to the disease
The prospective study is expensive and time
consuming but it has its advantages over
retrospective method

This method can help in studying the natural
history of disease, estimating incidence rates,
risk of developing disease.
It also helps to identify the relationship of the
risk factors under study to other disease or
problems e.g. cigarette smoking and high
blood pressure, cardio-vascular problems etc.

b. Retrospective cohort study
This is also called as historical cohort study. In this
type of study designs the event has already occurred.
 The investigator goes back in time – 10 to 30 years
and identifies the cases from existing record to be
included in the study group.
He then traces them from past fixed date forward to
present time or any other known date i.e. from
January 1975 to date or may be up to December 1995.
Retrospective cohort study designs have been most
useful for determining the effect of occupation
hazards. It is because the record is easily available e.g.
study of lung cancer in uranium miners. To conduct
cohort studies there are three essential requisities:

It must be possible to identify from records the members
of some previous existing group e.g. industrial workers
who were exposed to a suspected cause in the past.
Information about the factor under study is available
from the record or it can be reconstructed.
Information about the outcome i.e. disease or death for
the cohort is available.
hospital records can help in designing cohort studies
for determining causal relationship for various diseases.
These studies can be done in a short period and are
economical in comparison to prospective cohort study.

c. Combination of retrospective and

prospective cohort study
This design has the characteristics of both
retrospective and prospective studies. The
investigator identifies the cohort from past
record and traces forward till date. The same
cohort is followed up further for assessment
prospectively up to desired period.

Advantages:-
Incidence can be calculated.
Several possible outcomes related to exposure
can be studied simultaneously.
Cohort studies provide a direct estimate of
relative risk.
Disadvantages:-
Very expensive & time consuming.
Cohort study involves large number of peoples.

(b) Case-control studies:
Often called retrospective studies.
In this design, causes of a disease are investigated after
the occurrence of a disease.
For example, a researcher investigates the history of
smoking in patients diagnosed with lung cancer.  
Features:-
Both exposure & outcomes (disease) have occurred
before the start of the study.
The study proceeds backwards from effect to causes.
It uses a control or comparison group to support or
refute an inference.

In this method a group of people who have
been diagnosed as having a particular
problem e.g. lung cancer (cases) are
compared with a group of people who are
similar in characteristics to that of cases but
they are free from the problem i.e. free from
lung cancer under study (control). Here the
approach used is retrospective

Retrospective approach
 i.e. the disease have already occurred and the
epidemiologist looks back over time for
presence or absence of suspected causal
factors in both cases and controls.
He reviews the records, interviews the cases
and their family members. The data thus
collected about the suspected factors is
analysed stastically to determine the extent of
its association with the disease. This method ,
therefore, is called as retrospective method.
It is also called as case comparison design.

This approach have helped in identification of causative
factors of many diseases\problems etc.
Rubella in mothers during early pregnancy is the
cause of congenital deformities in children, smoking
associated with lung cancer, iodine deficiency
associated with hyperthyrodism.
These conclusions are based on repeated case control
studies. Case-control studies are easy to organize and are
less expensive but very effective in determining the risk
factors.
The major drawback of this design is difficulty in
selecting the control group.

Advantages:-
Relatively easy to carry out.
Rapid & inexpensive.
Particular suitable to investigate rare diseases about
which little is known.
No risk to subjects.
Ethical problems minimal.
Disadvantages:-
A problem of bias relies on memory or past records.
Selection of an appropriate control group may be
difficult.
We cannot distinguish between cause & associated
factors.

 SURVEY
RESEARCH
DESIGN

Introduction……
 A survey is a research research design is
used to collect information from different
subjects within a given population having same
characteristics of interest. If survey is conducted
on a sample of population, it is called sample
survey, if the entire population is involved,
called population survey. exp. Cencus.
 

 
Main features…..
Survey research is the process of gathering
current required data from the subjects so that
new information can obtained.
Survey research is a mode of inquiry that relies
heavily upon the validity of verbal reports.
Survey data can be collected in numbers of ways.
Exp.- face to face, questionnaires, interview etc.
Personal interview is most useful method to
collecting survey data because the quality of
information can be obtained.

Types of survey
Depending on the nature of phenomenon under
study:
Descriptive survey- Describe the frequency of
occurrence of a phenomenon is collected.
Exploratory survey- it is the survey of a phenomenon
& its related factors about which much is not known.
Comparative survey- comparing & contrasting the
existence of a certain phenomenon in two or more
groups.
Correlational survey- it is a study of the relationship
between two or more variables in a natural setting
without control.

Based on methods of data collection:
Written survey- data is collected with the help
of written, structure tools. Exp questionnaires,
opinionnaries etc.
Oral survey- by face to face, telephonic, oral
interview etc.
Electronic survey- collecting by e mails, web
forms, SMSs etc.

ADVANTAGE OF
NONEXPERIMENTAL RESEARCH
DESIGN
Nonexperimental research designs tend to be closest
to real-life situation.
Nonexperimental research designs are most suitable
for the nursing research studies..
Numerous human characteristics are inherently not
subject to experimental manipulation (e.g. blood type,
personality, health beliefs, medical diagnosis, etc.)
There are many variable that could technically be
manipulated, but manipulated is forbidden on ethical
grounds.

DISADVANTAGES OF
NONEXPERIMENTAL RESEARCH DESIGN
The major disadvantage of nonexperimental
researches is that the results obtained & the
relationship between the dependent & independent
variable can never be absolutely clear & error-free.
Nonexperimental studies are conducted for
comparative purposes using nonrandomly selected
groups, which may not be homogeneous & tend to be
dissimilar in different traits or characteristics, which
may affect the authenticity & generalizability of the
study results.

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