02 basic researchmethod

Chapter 02

Basic Research
Methodology

Definition

RESEARCH

Research is a quest for knowledge through
diligent search or investigation or
experimentation aimed at the discovery and
interpretation of new knowledge. (WHO)

Research is an art of scientific investigation.

Definition

RESEARCH

A systematized effort to gain new knowledge
(Redman).

A careful investigation or inquiry specially
through search for new facts in any branch of
knowledge (Advanced learners’ Dictionary)

Scientific Research Steps

1. Formulation of problems
2. Setting research objectives
3. Designing the study
4. Methods of data collection
5. Statistical analysis
6. Interpretation and dissemination of
the results

Empirical Theoretical / Conceptual

Philosophical

Categories of Research

Basic and applied Other categories

EMPIRICAL RESEARCH

Health research mainly follows the empirical
approach.
It is based on observation and experience more
than upon theory and abstraction.
It can be qualitative & quantitative.
Health Science Research deals with information
of a quantitative nature.

Empirical Research involves:

The identification of the population of interest.

The characteristics (variables) of the individuals
(units) in the population.

The study of variability of these characteristics
among the individuals in the population.

Quantification in Empirical Research:
Measurement of variables.

Estimation of population parameters.

Statistical testing of hypothesis.

Empirical research relies on experience or
observation without due regard to system or
theory.

THEORETICAL / CONCEPTUAL RESEARCH

It is related to some abstract idea(s), theory.

E.g. • In abstraction with mathematical models.

• Advances in understanding of disease
occurrence and causation cannot be made
without a comparison of the theoretical
constructs with that which we actually
observe in populations.

Empirical & theoretical research complements each
other in developing an understanding of the phenomena,
in predicting future events.

Basic / fundamental / pure

Research
Functional division

Applied

BASIC / FUNDAMENTAL / PURE

It means formation of theory or generalization.

Basic research is usually considered to

involve a research for knowledge without a

defined goal of utility or specific purpose.

APPLIED / ACTION
Solution for immediate problems.
Applied research is problem oriented.

OTHER CATEGORIES OF RESEARCH

Longitudinal / one time.
Field setting / laboratory / simulation.
Clinical / diagnostic.
Historical.
Conclusion oriented / decision oriented.

Bio-medical
(Cellular Research)

Health
Research
Triangle

Behavioral Health Research
(Beliefs / attitudes / practices (Environmental)
in the society by man)

SCIENTIFIC FOUNDATIONS OF RESEARCH
ORDER

Scientific method is not common sense.
In arriving at conclusion “common sense” can’t
be employed e.g. – Fever is a symptom of the
To arrive at conclusion an organized observation
of entities or events which are classified or
ordered on the basis of common properties and
behaviors are required.

It is this commonality of properties and
behaviors that allows predictions which
carried to the ultimate, become laws e.g.
A number of Allergic Rhinitis cases are
studied and it is found a number cases
are having a group of common causes
from which prediction is made and there
after etiology become conclusive as
from ‘Allergens’.

INFERENCE AND CHANCE

Reasoning or inference is the force of
advances in research.
In terms of logic, It means that a statement
/ or a conclusion ought to be accepted
because one or more other statements /
premises (evidence) are true.
Inferential suppositions, presumptions or
theories may be so developed, through
careful constructions, as to pose testable
hypothesis.


The testing of hypothesis is the
basic method of advancing
knowledge in science.

Two distinct approaches or
arguments have evolved in the
development of inferences. They are
such as: deductive and inductive.


In deduction, the conclusion necessarily
follows from premises (evidence) /
statements, as in syllogism e.g. [All ‘A’ is
‘B’, all ‘B’ is ‘C’ therefore all ‘A’ is ‘C’] or
in algebraic equations.
Deduction can be distinguished by the
fact that it moves from the general to the
specific.

It dose not allow for the elements of
chance or uncertainty.

Deductive inference, therefore are
suitable to theoretical research.

INDUCTION

Inductive reasoning is distinguished by the fact
that it moves from the specific to the general
(from sample to population). It builds:-

Health research being primarily empirical depends
entirely upon inductive reasoning.

The conclusion dose not necessarily follow from
the premises or evidence (facts). We can say only
that the conclusion is more likely to be valid if the
premises are true, i.e. there is a possibility that the
premises may be true but the conclusion is false.

Scientific Foundations of Research
Evaluation of probability
It is a critical requirement in research design.
Evaluation of probability ensures validity.
The most salient elements of design, which are meant to ensure
the integrity of probability and prevention of bias, are:
a) Representative sampling.
b) Randomization in the selection of study group.
c) Control group for comparison.
d) Blinding of experiment.
e) Use of probability (statistical) method in analysis &
interpretation.
Probability is a measure of uncertainty or variability of the
characteristic among individuals in the population.

HYPOTHESIS (A guess or imaginary idea)
Hypothesis are carefully constructed statements
about a phenomenon in the population.
It may be generated by deductive or inductive
reasoning from prior observations.

SOURCE OF HYPOTHESIS
a) General culture
b) Scientific theory
c) Analogies
d) Personal experience

Method of difference

Method of Mill’s Canons of Method of
Analogy Inductive Reasoning agreement

Method of
concomitant variation

QUALITIES OF WORKABLE HYPOTHESIS

a) Specific
b) Conceptually clear
c) Related to available technique
d) Capable of empirical test
e) Simple

UTILITY IN RESEARCH

a) Hypothesis gives point to inquiry.

b) Hypothesis helps in deciding in which to proceed.

c) Hypothesis helps in selecting pertinent facts.

d) Hypothesis helps in drawing specific conclusion.

STUDY DESIGN

Experimental type
Observational type
of research
of research

Testing of hypothesis is best
A sample of population done by experiments.
is observed for various
characteristics. Factors other than those
under consideration can be
controlled.
Not often possible in human
diseases due to ethical and
practical considerations.

Research Designing and Methodology

Definition of problem
e.g. Occurrence of lower
respiratory tract infection in
children after vaccination.

Selection of research topic
should be based on

• Magnitude of the problem and its impact
• Urgency of the need for a solution.
• Relevance to the aim of the funding agency.
• Amenability of the problem to investigation.
• Feasibility of the approach.
• Chances of success, etc.

Aim and Objectives

e.g. Whether nature of the problem
has to be studied or solution has to be
found by different methods.

Review of Literature
Critically review the literature on the problem
under study:
• Any such work done by other in the past.
• State whether you want to confirm the
findings.
• Challenge the conclusion.
• Extend the work further.
• Bridge some gaps in the existing
knowledge.

Hypothesis

An assumption, positive or negative.
e.g. Crataegus Q is not more effective
than Crataegus in potency.
Constitutional medicines act better then
mother tinctures for hypertension, etc.

A) Definition of the population under study

I. It may be country / state / districts / town /
village / families / specific groups.
II. Age group
III. Income group
IV. Occupation
V. Sexes
VI. Define clearly who are to be included and
who are not to be included, i.e. (Inclusion
and exclusion criteria)

B) Selection of the sample

• It should be unbiased.

• Sufficiently large in size to
represent population under study.

Sample size

For Qualitative Data

N = 4pq/L2

Where ‘p’ is the positive character, q =1-p
L= allowable error, 10% or 20% of ‘p’

For Quantitative Data

L=2σ/√n or √n=2σ/L or
n= 4σ2/L2

Sample size for analytical studies:

a. Testing equality of two proportions: π1 = π2
n = [{Z 1-α √ 2⎯π (1 -⎯π) - Z β √ π1 (1- π1) + π2 (1 - π2)} / δ] 2

Where ⎯π = (π1 + π2) / 2

b. Sample size for a case - control study
c. Comparison of two population Means.
n = [(Z1-α - Zβ) σ / δ ]2
d. Comparison of more than two groups and methods.

Sampling methods

i) Simple random sampling
- Choose random number from the
table.
ii) Stratified sampling
- (Selecting 50% male & 50% female)
iii) Systemic sampling
- Systematically it is chosen.

iv) Cluster sampling
- Cluster may be identified
(households) and random
samples of cluster.

v) Multistage sampling
- In several stages.

Specifying the nature of study

Epidemiological studies:
These are field and not hospital
based.
Studies are more likely to be
unbiased.
e.g. Infant mortality is higher
in rural than in urban areas.

Nature of Study
a) Longitudinal
Observations are repeated in the same
population over a prolonged period of time
by means of follow up examinations.
• Prospective study: Longitudinal follow up
of population over a period of time.
• Retrospective study: Longitudinal study
in profile of a sample or population. E.g.
Mortality of women over 45 years.

Nature of Study

b) Cohort studies:
Longitudinal studies in which the
sample is a cohort. A cohort is a
group of persons exposed to same
sort of environment. E.g. women
between 15 to 45 yrs. exposed to
radiation.

Nature of Study

c) Interventional studies:
It involves three phases:
• Diagnosis or identification phase
• Intervention by treatment or
service for a specific
• Assessment phase for result.

Nature of Study

d) Experimental studies: Trials are made such
as a drug or medical service and the result is
watched.
e) Cross-sectional studies: (Non-experimental):
Onetime or at a point of time study of all
persons in a representative sample of a specific
population. E.g. Examination of all children in
age group 5 to 14 yrs. detection of cancer cases
and study of the factors that lead to cancer.

Nature of Study

f) Control studies:
• Control group should be identical to the
experimental group in all respects except
for the factor under study.
• Sometimes not possible so ignored. E.g.
Withdrawing antibiotic in pneumonia.
• Sometimes not required. E.g. Prevalence of
cancer in smokers (sufferers) is compared
with prevalence of cancer in non-smokers
(controls).

Ruling out subjective bias
in subjects under study

a) Single blind trial

b) Double blind trial

Errors in the inference

Two common sources of errors

that needs to be controlled result from

problem with ‘reliability’ and

‘validity’.

Reliability

If the observations are repeated under similar
conditions the inference should to be similar.

Reliability of the sample is achieved by
selecting a large sample.

Reliability is measured by using ‘random
error’

Validity
The inference should be reflection of the

true nature of the relationship.

Validity is achieved by insuring the

sample selection is unbiased.

Validity is measured by using ‘bias’.

Statistical Tools or Tests of Significance
Z – test
Z = X - μ / SE (X)
(between sample means)

Where X = Sample mean
μ = Population mean
SE = Standard error

Z = Observed difference between two sample
means / Standard error of difference between
two sample means (between two sample means)

Requirements to Apply Z – Test:

1. The sample or samples must be randomly
selected.

2. The data must be quantitative.

3. The variable is assumed to follow normal
distribution in the population.

4. The sample size must be larger than 30.

t – test

Requirements to Apply t – Test:

1. The sample or samples must be randomly selected.
2. The data must be quantitative.
3. The variable is assumed to follow normal distribution
in the population.
4. The sample size must be less than 30.

t = X - μ / SE (X)

Where X = Sample mean
μ = Population mean
SE = Standard error

Chi – square Test (χ2 test)

It has got the following three very important
applications in medical statistics as tests of:

• Proportion – To find significance in same type of
data.

• Association between two events.

• Goodness of fit – To test fitness of an observed
frequency distribution of qualitative data
to a theoretical distribution.

To apply χ2 test

Three Essential Requirements:

• A random sample

• Qualitative data

• Lowest expected frequency (value) not less than 5

χ2 = ∑ (O – E)2
E

Where O = Observed value

E = Expected value

Variance Ratio Test: (F – test)

This means comparison of sample variance. It is
applied to test the homogeneity of variances.

F = S12 / S22

S1 2= Variance of first sample (S12 > S22)

S22 = Variance of second sample

ANOVA Test (Analysis of Variance Test)

This test is not confined to comparing two
sample means but more than two samples
drawn from corresponding normal population.

Presentation in brief
1. Title of the Article
2. Abstracts
A brief summary of the work done.
Major observations and results.
3. Introduction
Name of the problem
Clear reasons for understanding the particular
research.
Put forward the hypothesis.
Enumerate aim and objectives of the study.

4. Review of Literature
5. Materials and Methods
Definition of population under study
Selection of sample
Nature of study
Ruling out the observational and instrumental
errors.
6. Results
Presentation of data.

7. Analysis of the results
Unbiased statistical analysis

8. Discussions
Compare the results obtained in your work with
those in the literature.
Discuss the reasons for differences and
similarities
Mention pitfalls in your study.

9. Conclusion: A short account of findings.

10. Recommendations or constructive suggestion

11. Acknowledgements

12. Bibliography or References

13. Appendices

02 basic researchmethod

More Related Content

What's hot (20)

Similar to 02 basic researchmethod (20)

Recently uploaded (20)

02 basic researchmethod