The document outlines a comprehensive research methodology including study design, sampling techniques, data collection, analysis, and levels of evidence in the context of health research. It emphasizes the significance of research in improving knowledge, informing policies, and guiding evidence-based practice while detailing various research types, methods, and potential challenges. It also discusses the evaluation of evidence and recommendations with a grading system to assess clinical relevance and decision-making in healthcare.

1. RESEARCH METHODOLOGY
(DESIGN OF STUDY, SAMPLING, DATA COLLECTION AND
ANALYSIS, LEVEL OF EVIDENCE AND GRADES OF
RECOMMENDATION)
Dr Uttam Nepal
2nd yr Resident
MS ENT-HNS
KIST MCTH

2. ROADMAPS:
 Research: Introduction and its Types
 Study design: Different types of study design
 Sampling : Differnet techniques and its importance
 Methods of data collection, analysis and interpretation
 Evidence and recommendations.

3. If we knew what it was we were
doing, it would not be called
research, would it?
Albert Einstein

4. RESEARCH

5. RESEARCH
 French "recherche“ - to go about seeking
 Research is a quest for knowledge through diligent search or investigation
or experimentation aimed at the discovery and interpretation of new
knowledge (WHO).
 Redman and Mory defined research as a “ systematized effort to gain new
knowledge .”
 CliffordWoody : Research comprises of defining and redefining problems ,
formulating hypothesis, collecting, organising and evaluating data, making
deduction and reaching conclusions and at last carefully testing the
conclusions to determine whether they fit the formulating hypothesis

6. RESEARCH: NEED AND PURPOSE
 Improve existing knowledge – generate new technologies
 Identify priority problems – design and evaluate policies to deliver greatest
health benefit with available resources
 Open the new horizon for research

7. RESEARCH: SIGNIFICANCE
 Evidence based practice
 Treatment protocol
 Treatment of sudden sensorineural hearing loss with IV steroid
 Policy making
 Iodine supplementation in salt to prevent goiter in adolescence
 Problem identification and prioritization
 Quality of health service
 Driving force – new research

8. RESEARCH: IMPORTANCE
 As a postgraduate student
- To critically analyse the information
- Thesis preparation
 As future practitioner
- Evidence based practice
- Professional status
- Participate in research projects
 As an educated citizen
- To understand difference between scientifically acquired information and others

9. RESEARCH: FIELDS OF APPLICATION
 Useful in policy making
 Treatment protocol
 Investigation
 Sequel/Complication
 Quality of service
 Actual size of problem
 Avenue for further research

10. TYPES OF RESEARCH
 Basic research
 To generate new knowledge
and technologies
 In vitro / in vivo experiments
(animal experiments)
 eg. p53 gene mutation in
HNSCC
 Applied/Action research
 Involving practical application
 eg. Monoclonal antibody
therapy in HNSCC
 Discriptive research
 Eg. Prevalence of ca larynx in adult
population in Kathmandu
 Analytical research
 Eg. Role of environmental pollution
in allergic rhinitis

11. TYPES OF RESEARCH
 Quantitative research
o Based on the measurement of
quantity or amount
o eg. Recurrence rate of sinonasal
polyp after FESS
 Qualitative research
o Relating to quality or kind
o eg. Quality of life after surgery
for head and neck cancer
 Outcome research
o Impact of intervention on the patient
in terms of health status and health
related quality of life
o eg : Hearing outcome after butterfly
cartilage tympanoplasty
 Experimental research
o Comparing two groups on one
outcome measure to test some
hypothesis regarding causation
o eg. Comparison of dexamethasone
versus bupivacaine in reducing
early postoperative pain after
tonsillectomy in children

12. TYPES OF RESEARCH
 Conceptual / Empirical
 Field-setting research or laboratory research or simulation research
 Clinical or diagnostic research
 Health systems research
 Exploratory
 Historical research

13. HEALTH RESEARCH: TYPES

14. RESEARCH METHOD AND METHODOLOGY

15. COMPONENTS OF RESEARCH
 Conceptualizing the problem
o Statement of problem
o Research questions
o Rationale
 Literature review
 Formulating objectives
 Developing testable hypothesis
 Ethical considerations
 Workplan

16. SELECTION OF TOPIC
 Interest
 Relevance
o Magnitude of problem
o Severity of problem
o Population affected
 Avoidance of duplication
 Feasibility
 Political acceptability
 Applicability
 Cost effectiveness
 Ethical consideration

17. RESEARCH QUESTION
 “Uncertainty” about something in the population that the investigator wants
to resolve by making measurements in the study population .
 It is best to frame the research question using the PICO format
P- Population/patient/person with(or at risk of) a health problem on which
research is based.
I- Interventions
C-Comparisons
O-Outcome
Often (T) – Time frame is also added to the PICO format

18. RESEARCH(CONTD.)
Components of a Good Research
 Feasible- Adequate number of participants , technical expertise and
resources .
 Interesting
 Novel – Provides new information
 Ethical- Amenable to a study that ethics committee will approve
 Relevant - To the scientific world of knowledge / clinical practice/ health
policy.

19. STUDY DESIGN

20. STUDY DESIGN

21. STUDY DESIGN: TYPES
 Non intervention studies
 Exploratory studies
 Descriptive studies
 Comparative or analytical studies
 Cross sectional
 Case - control
 Cohort
 Intervention studies
 Experimental studies
 Quasi – experimental studies
 Parallel design
 Cross over design
 Factorial design
 Meta Analysis

22. NON INTERVENTION STUDIES
Exploratory Study
• To gather preliminary information that
will help define problems and suggest
hypotheses
• Helps in selection of:
• Best research design
• Data collection method
• Selection of subjects
• Audits
• E.g. Quality of discharge Summary in
different department of KISTMCTH
Descriptive study
• In-depth description of characteristic
of one or limited number of cases.
• Case studies: case report of
uncommon diseases
• e.g.. B/L facial nerve palsy
• Case series

23. CROSS SECTIONAL STUDY
 Quantifying distribution of variable in population at a point of time
 Quantify disease burden
 Useful for hypothesis generation
 Covers a sample of population
 Total population covered:- census
 E.g.. Prevalence of COM, children with OME
OUTCOME
EXPOSURE
STUDY

24. CROSS SECTIONAL STUDY
Advantages:
 Cheap and simple;
 Ethically safe.
Disadvantages:
 Establishes association at most, not causality;
 Confounders may be unequally distributed;
 Group sizes may be unequal.

25. CASE CONTROL STUDY
 Compares one group with problem to
another group without
problem(control group)
 Retrospective from outcome to
exposure
 Confounding factors
EXPOSURE STUDY DISEASE

26. CASE CONTROL STUDY
 Odds Ratio:
o Chances that a case was exposed
to risk factor to the odds that a
control was exposed to risk factor
o Estimation of risk & not a true
risk value
Case Ca Larynx Control Without
Ca
Smoking 33(a) 55(b)
No smoking 2(c) 27(d)
Odd Ratio: a x d/ c x d – 8.1

27. CASE CONTROL STUDY
Advantages:
 quick and inexpensive;
 Good for rare disorders or those with long lag between exposure and
outcome;
 fewer subjects needed than cross-sectional studies.
 Possibility of exploring multiple exposures
Disadvantages:
 reliance on recall or records to determine exposure status;
 confounders;
 selection of control groups is difficult;
 potential bias: recall, selection.

28. COHORT STUDY
 Group exposed to risk factor (study
group)  compared with group not
exposed (control group)
 Prospective study, Incidence
 Longer, labour intensive, expensive &
loss to follow up
EXPOSURE STUDY OUTCOME

29. COHORT STUDY
 Relative Risk (RR):
 Incidence among exposed/ Incidence among non exposed = a/(a+b)/c/(c+d)
 True estimate of risk,  value- strength
 Interpretation of Relative risk:
• RR =1: no association
<1: protective effect
<2 : weak association
>30: almost aetiological association
Ca Larynx No Ca Larynx Total
Smoker 60(a) 40(b) 100 (a+b)
Non smoker 30(c) 70(d) 100 (c+d)
RR:Incidence in Exposed/Incidence of non exposed-60/30-2

30. COHORT STUDY
Advantages:
 ethically safe;
 subjects can be matched;
 can establish timing and directionality of events;
 eligibility criteria and outcome assessments can be standardized;
Disadvantages:
 controls may be difficult to identify;
 exposure may be linked to a hidden confounder;
 blinding is difficult;
 randomization not present;
 for rare disease, large sample sizes or long follow-up necessary.

31. INTERVENTION STUDIES
 Experimental study
o Randomized Control Trial( RCT)
• Randomization, Control, Blinding
o Quasi- Experimental Studies
o Parallel Design
o Cross-over design
o Factorial design
 Meta analysis

32. RANDOMIZED CONTROLLED TRAILS(RCT)
 Can actually prove causation
o At least 2 groups (experiment or intervention & non-intervention)
 Three characteristics:
 Randomization : to allocate subjects to control & experimental group
 Control: to compare with experimental group
 Manipulation: some intervention to one group

33. QUASI- EXPERIMENTAL STUDY
 Study little or no control over allocation of the treatments or other factors
being studied
 The key difference : lack of random assignment  impractical or unethical
 Easier to set up, minimizes external validity
 Threat to internal validity, value of result less than RCT

34. PARALLEL DESIGN
 Parallel Groups
 Multiple concurrent experimental arms
o Different treatments
o Different doses
 Control arm(s)
o Placebo, active control
 Balance/imbalanced randomization
 e.g. ISSNHL :- Placebo, i.v steroid, IT steroid

35. CROSS OVER DESIGN

36. CROSS OVER DESIGN

37. FACTORIAL DESIGN
 Evaluates two interventions
simultaneously
 Four possible treatment combinations
 Efficient approach in some
circumstances
 Potentially more informative
approach
 Major concern: interaction of
interventions

38. CLINICAL TRAILS PHASES
• Phase I: Normal volunteers
• To find Maximum tolerated dose
• Phase II: Patients with Diseases
• To establish effects & side effects
• Phase III: Clinical trial
• Phase IV: Long term
surveillance
Phase I
Phase II
Phase III
Phase IV

39. SAMPLING

40. SAMPLING
 Population or Universe: a set of all individuals or
objects having common characteristics
 Sample: subset or part of the population
 Sampling: Process or technique of selecting a sample of
appropriate & manageable size for study
 Sampling unit: breakdown parts of population which are
distinct, unambiguous & non-overlapping
 e.g.. Hospitals, 15-25 yrs

41. SAMPLING
Advantages
 Reduces cost of study considerably
 Greater speed (less time)
 Greater accuracy
 Increase scope of study: several aspects
 Some tests not possible in population can be applied
 Study can be in depth & more subtle

42. RELIABLE SAMPLE
 Efficient
 Representative
 Measurable
 Sizeable
 Coverage
 Goal oriented
 Representative of underlying population
 Feasible
 Economic & cost efficient

43. ERRORS
 Sampling errors
 Repeated sample from same population, result different
 Collection, processing, analysis
 Decrease by increasing sample size
 Non sampling errors
 Observational & defective measurement technique
 Error in editing, coding & tabulating results
 Increased by increasing sample size

44. TYPES OF SAMPLING
A. Probability
Each element has equal chance of being included
• Simple random
• Systematic random
• Cluster
• Stratified
B. Non-probability
Each element may not have same chance
• Convenience
• Purposive
• Quota sampling

45. SIMPLE RANDOM SAMPLING
 Equal chance
 Decided by law of chance
 Provides greatest number of
possible sample
 Small sample-Lottery
 Large sample-Table

46. SYSTEMIC RANDOM SAMPLING
• Pre determined system is followed
• Number of possible sample is greatly reduced
• Every 3rd
or 10th
• First sample is selected randomly

47. CLUSTER SAMPLING
 Selection made of cluster
 E.g..VDC, tole/ward; military
camp; School
 Prevalence of OME among
children in day care

48. STRATIFIED SAMPLING
 Population divided into different
strata
 E.g.. Religion; socioeconomic
status
 Random sampling done in each
strata proportionate sampling less
likely to miss smaller group
 e.g.. If out of 1000 in a community,
planned for 100
 Hindu = 850; sample = 85
 Muslim = 100; sample = 10
 Christian = 50, sample = 5

49. NON PROBABILITY SAMPLING
 Convenience:
oHaphazard, non representative
oPurpose usually for exploratory
oPatient visiting ENT OPD
 Purposive:
oPredetermined idea
oResults can not be generalized
oNatural history of AOM in immunodeficiency
 Quota sampling:
o Population divided into mutually exclusive groups and subjects or unit
selected by judgment and not randomly

50. PROBABILITY VS NON PROBABILITY SAMPLING

51. DATA COLLECTION AND
INTERPRETATION

52. VARIABLES
 Variable
 Any observation that can take on different values
 Attribute
 A specific value on a variable
Variable:Age,Gender
Attribute: 18/19/20,Male/Female
 Types of Variables:
o Independent Variables vs. Dependent Variables
o Qualitative Variables vs. Quantitative Variables

53. VARIABLES
 Qualitative / categorical
variable
Non-numerical values
o Dichotomus: Antibiotic use
–yes/no, Gender-Male/Female
o Polychotomus: Nationality
o Ordinal: Disease severity
–mild/moderate/severe
 Quantitative variable
Intrinsically numerical
o Continuous – Hearing threshold
o Discrete – Number of attacks of
tonsillitis

54. VARIABLES
Independent variable
 Factor that is assumed to cause / influence the problem
e.g. Smoking in the study of relationship between smoking and laryngeal
cancer
Dependent variable
 Factor that gets modified under influence of independent variable
e.g. Suffering from laryngeal cancer

55. SCALES OF MEASUREMENT
 Nominal
o Qualitatative data (Male, Female)
 Ordinal
o Categories are ranked
o eg . Pain - Mild, Moderate, Severe
Stage of cancer – I,II, III,IV
 Interval
o Intervals between Classes equal, zero point arbitrary
o eg. Pain scale (1-10)
IQ score (90,95,100)
 Ratio

56. STUDY INSTRUMENTS
Tools by which data are collected
 Questionnaire and interview schedules
 Other methods:
o Medical examination
o Laboratory tests
o Screening procedures
o Previous hospital records
o Survey
o Focus group discussion
 Designing of recording forms
 Mailing/telephone/e-mail/face to face interview

57. PURPOSE OF DATA COLLECTION
 Get information
 Monitor progress
 Evaluate performance & use of resources e.g. audit
 Identify gaps between knowledge & practice
 Evaluate impact of programs
 Make decision
 Utilize in planning

58. DATA COLLECTION: STEPS
 Identification of objective
 Listing target population
 Identification of time frame
 Selection of data collection instrument
 Development of data collection method
 Selection of proper sampling design
 Organization
 Precoding
 Pretesting
 Field survey launching

59. DATA ANALYSIS AND INTERPRETATION
Plan for analysis beforehand
Description should include
 Design of analysis form
 Plan for processing & coding data
 Choice of statistical method

60. CRITERIA IN SELECTING APPROPRIATE
ANALYTICAL METHOD
 Objectives of the study
 Design of the study
 Scale by which the variables are measured
 Sample size
 Number of variables to be analyzed

61. METHODS OF DATA INTERPRETATION
PRESENTATION
 Table:
o Simple
o Should be numbered
o Self explanatory title
o Heading of rows or column clear & concise
o Foot note may be given
o Presented according to size or importance

62. METHODS OF DATA INTERPRETATION PRESENTATION
GRAPHS:
 Methods of showing quantitative data using a coordinated system
o Arithmetic scale line
o Semi logarithm scale line
o Histogram
o Frequency polygon
o Scatter diagram

63. METHODS OF DATA INTERPRETATION
PRESENTATION
 Charts:
 Bar
 Pictogram
 Pie
 Geographic co-ordinate
 Flow
 Organization

64. METHODS OF DATA PRESENTATION
 Percentage
o no of units with certain characteristics x100
no of units in sample
o n = 50 ; M = 20 : F = 30 ; % of M = 40%
 Proportion
o Compares relation in magnitude one part of study unit to whole
o M = 2/5 : F = 3/5
 Ratio
o Relation in size between 2 or more parts
o M:F=2:3
 Rate
o Amount or degree of something measured in specific period of time

65. MEASUREMENTS
 Measures of central tendency
o Mean
o Median
o Mode
 Hb of patients admitted with epistaxis
(in Gm%)
13.2, 9.5, 11.7, 13.6, 10.4, 11.7, 9.9,
14.0, 12.4, 11.9, 10.3
o Mean = 11.7
o Median = 9.5, 9.9, 10.3, 10.4, 11.7,
11.7, 11.9, 12.4, 13.2, 13.6, 14.0
o Mode = 11.7

66. MEASUREMENTS
Measurement of dispersion
 Range:
o Difference between largest and smallest value
 Percentiles:
o Parts that divide measurements into 100 equal parts
o e.g. 3rd
percentile, 10th
percentile
 Standard deviation:
o Measure which describes how much individual measurement differs on an average
from mean
o ± 1 SD = 68.2%
o ± 2 SD = 95.4%
o ± 3 SD = 99.6%

67. DATA ANALYSIS
 Manually
 Using computer programs
o Excel
o Data base
o SPSS
o Epi-info
o SAS: Statistical Analysis Software

68. DETERMING DIFFERENCE BETWEEN GROUPS

69. SIGNIFICANCE TEST APPLICATION
Difference between groups
 X2
test
 Sign test
 t-test
Association between groups
 X2
test
 Odds Ratio
 Relative Risk
 Pearson’s
 Spearman's

70. SIGNIFICANCE TEST APPLICATION
 Chi Square test
 Criterion for using 2- test
 Data should be categorical or
qualitative one
 2- test is used to:
 Find out the significance of difference
between two proportion
Find out the association or relation
between two variables
 Students’T test
• Criterion for using t-test
 distribution should be normal
 data set may be quantitative
 sample size  30
 Z test
• Criterion for using Z-test
 Distribution should be normal
 Data set may be qualitative or quantitative
 Sample size  30
Spearmans’s rank correlation coefficient()
 = 1 - 6  d2
/ n ( n2
– 1)
Where,
d - difference of paired ordered observations &
n - number of paired observations

71. EVIDENCE AND
RECOMMENDATION

72. EVIDENCE
 Evidence
a thing or things helpful in forming
a conclusion or judgment
 Evidenced –Based Medicine
“the integration of the best
research evidence with clinical
expertise and patient value”
“conscientious, explicit and
judicious use of current best evidence
in making decisions about the care of
individual patients” sackett et al 1996
BMJ

73. LEVEL OF EVIDENCE

74. LEVEL OF EVIDENCE
 Level A: Consistent Randomized Controlled Clinical Trial, cohort study, clinical
decision rule validated in different populations.
 Level B: Consistent Retrospective Cohort, Exploratory Cohort, Ecological Study,
Outcomes Research, case-control study; or extrapolations from level A studies.
 Level C: Case-series study or extrapolations from level B studies.
 Level D: Expert opinion without explicit critical appraisal, or based on physiology,
bench research or first principles.

75. QUANTIFICATION OF EVIDENCE

76. GRADES OF RECOMMENDATION
 Grade A: Good scientific evidence suggests that the benefits of the clinical service
substantially outweighs the potential risks. Clinicians should discuss the service
with eligible patients.
 Garde B: At least fair scientific evidence suggests that the benefits of the clinical
service outweighs the potential risks. Clinicians should discuss the service with
eligible patients.
 Garde C: At least fair scientific evidence suggests that there are benefits provided
by the clinical service, but the balance between benefits and risks are too close for
making general recommendations. Clinicians need not offer it unless there are
individual considerations.

77. GRADES OF RECOMMENDATION
 Grade D: At least fair scientific evidence suggests that the risks of the clinical
service outweighs potential benefits. Clinicians should not routinely offer the
service to asymptomatic patients.
 Garde N : Scientific evidence is lacking, of poor quality, or conflicting, such that the
risk versus benefit balance cannot be assessed. Clinicians should help patients
understand the uncertainty surrounding the clinical service.

78. LEVEL OF EVIDENCE AND GRADE OF
RECOMMENDATON

79. SUMMARY
 Research is a quest for knowledge through diligent search or investigation or
experimentation aimed at the discovery and interpretation of new knowledge
 Research is very important aspect in medical field.
 RCTs are regularly done trails in medical field
 Sampling and its different methods are used for minimizing error
 Mean, mode and median are used for measuring central tendency ; Range,
percentile and SD are used for measuring dispersion
 X2
is used for measuring association and difference between groups
 Level of evidence and Grade of Recommendation are associated with each other

80. REFERENCES:
 Scott-Brown’s Otorhinolaryngology, Head and Neck Surgery, 8th
edition
 Park’s Text book of social and preventive medicine ,21st
edition

81. Thank
you