This presentation discusses research methodology to be followed in otological research.

1. Research
Methodology in
otology
BALASUBRAMANIAN THIAGARAJAN

2. What is ideal research?
 Should be reproducible
 Should withstand statistical analysis
 Should test a theory / hypothesis / belief
 Should be beneficial to the public
 Should be systematic / empirical / critical /
 Should have academic integrity
 Should be publishable
Desist finding questions to your answers

3. Confidence interval
Sample
Confidence interval
Population

4. Factors affecting confidence
interval
 Sample size – Larger the sample size better is the confidence interval
 Percentage – Represents the accuracy of the study
 Population size – This is least important provided the samples are
randomly selected. This is important when the group is relatively
small and contains known group of people

5. Confidence level
This tells the researcher how confident the actual mean falls within the
Confident interval. Standard deviation if applied tells the researcher
How much variation that can be expected with the studied sample
Size. Ideal SD value is 0.5.

6. Sample size calculation
Confidence level = Z This is a constant value
90% - confidence interval - Z score = 1.645
95% - confidence interval - Z score = 1.96
99% - confidence interval - Z score = 2.326
Sample size = (Z-score)2 * Std Dev* (1- SD) / (margin of error)2
((1.96)² x .5(.5)) / (.05)²
(3.8416 x .25) / .0025
.9604 / .0025
384.16

7. Research styles
 objective
 subjective
Ethical committee approval is a must for all types of research

8. Objective type
 Physical characteristics
 Testing universally applicable rules / laws
 Testing hypothesis
 Experiments
 Surveys
Avoid the lure of numbers. Observation of researcher is more vital

9. Subjective type
 Involves social life of groups
 This study is usually conducted by observation and the findings
documented and explanations attempted for the observations
 Usually social scientists use this modality
Always assume that your work will be scrutinised by the public

10. Types of objective study design
 Descriptive
 Analytical
 Interventional
Greatest danger is not failure but non submission of your work

11. Descriptive study design
These studies consider variance of disease in respect of time, place
and person. Classic example of this design would be an attempted
study on the incidence of age related degree of progressive sensori
neural hearing loss.
These studies provide clues that can be used to design elaborate
analytical studies.
Two types of descriptive studies are possible i.e. cross sectional and
longitudinal.

12. Cross sectional study (Descriptive Design)
 This study is based on single examination of cross section of
population performed at one point of time
 Results can be projected on the whole population provided the
study is random in nature
 This is a fast and inexpensive way of ascertaining incidence of a
disease

13. Cross sectional study - Steps
 Objective of the study should be clearly defined
 Population under study should also be defined clearly
 Disease / health problem to be studied should also be defined
clearly (diagnostic criteria should be laid down)
 Randomization of the sample should be ensured
 Double blind trial has more validity
 Make a list of variables
 Prepare a questionnaire
 Decide on a sample size

14. Longitudinal study (Descriptive design)
 Observations are repeated in the same population over a
prolonged period of time by means of follow up examinations
 Natural history of disease and its future outcome can be studied
 Helps in identification of risk factors in disease causation
 Also helps in finding out the incidence rate

15. Advantages of descriptive studies
 Provides morbidity and mortality data
 Provides clue to disease etiology
 Generates hypothesis which can be tested by analytical studies
 Provides data for planning, organizing and evaluating preventive
and curative services
 Contributes to research in terms of disease occurrence by time
place or person

16. Analytical study design
 Classic example of this design would be the study to ascertain odds
of developing noise induced hearing loss.
 Intensity / duration of noise exposure should be factorized.
 Age and sex of the patient (variables).
 Analytical study design could be prospective and retrospective

17. Prospective study design (cohort /
longitudinal)
 Difficult to perform
 Tests the hypothesis obtained by descriptive study
 Should proceed from cause to effect
 This study is carried out on healthy people on whom exposure has
occurred and disease has not
 Vulnerable groups should be followed over a period of time to
identify the risk factor
 Costly to perform

18. Cohort study design
Population
People without disease
Exposed Un Exposed
Disease No Disease Disease No Disease

19. Retrospective study (case control
study)
 Easy to design and perform
 This study is performed based on medical records
 Study includes cases with health problems and controls without
disease
 They should be matched evenly age for age and sex for sex to be
valid
 Randomisation is a must
 Cost of study affordable

20. Interventional study
 Interventional studies attempt to demonstrate the cause-effect
relationships by altering the natural history of the disease by
intervention aimed at reducing the exposure to the offending
agent. (Sound in this case)
 Control group should be included for comparison
 Randomization should be followed to remove bias
 Single / double blind protocol can be followed

21. Beware of variables
 They should be identified correctly
 Incorrect identification of variables will invalidate the entire research
 Factors that could invalidate the entire research should be listed
and factorised
 The trick is in trying to unearth surprising variables

22. List some of the variables in our
hypothetical project
 Intensity of noise in decibel
 Number of hours of exposure / day
 Exposure of workers to ototoxic drugs
 Surprising variable – temporary / permanent threshold shift

23. Common pitfalls
 Sample size
 Variables
 Improperly formulated questionnaire
 Improperly matched control

24. Types of sample
 Convenient sample (ideally suited for our research scenario taken
up here)
 Judgement sample (according to the one who is familiar with the
characteristics of the population under study)
 Random sample (gives the most accurate and validated result)

25. Sample size
 Don’t hesitate to take the help of statistician at this stage
 For any successful research the confidence level should at least be
above 90% with error value of a minimum 5-10%
 Avoid online sample calculators

26. Variables – dependent /
independent variables
 All experiments contain variables at least one if not more
 These can be measured / studied
 Dependent variable – is dependent on independent variable

27. Categorical variables
 Nominal variables – Can have two / more categories
 Ordinal variable – can have two / more categories that can be
ranked
 Dichotomous variable – can have only two categories (either or) like
male / female

28. Continuous variables
 These are quantitative
 Classified into interval or ratio variables

29. data analysis
 Attempt must be made to summarize the observed variables
 If many variables are taken into consideration then coding and
categorization should be performed
 Study of frequency distribution should be resorted to analyse
complex data
 Data should be displayed as bar diagram / pie chart / histogram /
frequency distribution curves / x-y plots

30. Line graphs
 Useful in tracking changes over a
period of time
 Smaller changes are better
displayed
 Can also be used to compare
changes over time even for more
than one group by changing the
colour of the line

31. Bar graphs
 Can be used to compare things
between different groups
 Can also be used to track
changes over course of time
 This graph suits best if the changes
are larger

32. Pie charts
 Best used when comparing parts
of a whole
 Cannot be used to show changes
over a period of time

33. Area graphs
 Similar to line graphs
 Can be used to track changes
over time
 Groups must be categorized
before displaying

34. X-y plot
 Used to determine relationships
between two different things
 X-axis is used to plot one variable
and the y-axis is used to plot the
other
 If both variables increase at the
same time it is positive relationship
 If one variable increases while the
other decreases it is negative
relationship

35. Mean / median / mode
 Mean – is nothing but an average. It is the sum of values divided by
the number of values
 Median is the value that divides the distribution into half
 Mode is the value that occurs most often

36. Variance / standard deviation
 This is the most preferred method of variation
 It uses all the observation
 Variations would be small if the observations are bunched closely
 Variations if averaged will always be zero because positive
deviations away from the mean would cancel out the negative
deviations away from the mean
 Squaring the average of deviations is resorted to, and this average
of squared value would always stay positive
 Standard deviation is a measure of how spread out the numbers
are. It is actually the square root of variance and is indicated by
Greek letter sigma

37. explanation
 Measured heights of dogs in mm
 Mean = sum of all the heights
divided by 5 (394 mm)

38. Explantion (contd)

39. calculation
 Variance can be calculated by squaring the differences and
averaging them (21704)
 Standard deviation is square root of variance = 147. This number
helps in comparison.
 Use p values / chi-square test to test hypothesis

40. Before choosing a topic
 Conduct feasibility study
 Is it possible to complete within the given time frame
 Affordability
 Institutional support
 Can you obtain necessary literature?
 Will the topic be relevant after the completion?

41. Check list
 Exact date of submission
 Any word limitations
 Intermediate deadlines to meet
 Rules regarding the publication format
 Tutorial support available

42. Points to be borne in mind
 No harm should come to participants in the research (physical /
mental / social)
 Children / elderly / mentally retarded should not be exploited
 No physical / environmental damage should be caused
 Anonymity / privacy should be ensured
 Nothing should be done that would bring disrepute to the institution

43. Interviewer conduct
 Friendly and formal
 Schedule to be followed
 Prior appointment to be sought
 Treat all interviewees the same
 Prompt don’t direct
 Do not volunteer answers
 Never be patronising
 Be patient

44. Some useful research topics in
otology
 Incidence of conductive deafness in children and their causes
 Incidence of noise induced hearing loss
 Measles infection – does it cause otosclerosis ?
 Acceptability of hearing aids
 Age related normal hearing in Indians

45. Title
 Start off with a draft title
 Keep polishing it
 Avoid question marks in title
 Include the period and place of study in the title if possible

46. aim
 Here the aim of the study should be stated
 Inclusion and exclusion criteria may be stated here as a
subheading (ideally done in materials and methods)

47. Introduction - chapter
 Should contain an outline of your research
 Should contain details of what prompted you to undertake the
study
 It should also state concisely what you plan to do and where you
plan your work
 Start writing this chapter first, edit it after completing the project

48. Literature review
 This is central to all research
 It informs the reader how well you have prepared for the topic
 Here you take the opportunity to acknowledge other’s work
 It also informs the reader the road you plan to take

49. Materials and methods
 Here the exact research methodology followed is described
 There should be a description of the tests used
 Inclusion and exclusion criteria should be discussed in detail

50. result
 Data should be presented
 Data analysis should be presented here
 Statistical tool used for the analysis should be discussed here

51. conclusion
 Take time writing this one
 Give your conclusions point by point in clear terms
 Results should not be repeated but summarized here
 Practical recommendations can be included here

52. Bibliography
 List down all the references and citations
 All references and citations should easily be identifiable

53. appendix
 The material given here is for optional reading
 Copy of questionnaire
 Interview schedule
 Copy of ethical committee approval
 Copy of institutional approval