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Thomas Songer, PhD
Introduction to Research Methods
In the Internet Era
Scientific Method
Identifying Hypotheses
Introduction to Research
Key Lecture Concepts
• Understanding the process described as
“the scientific method”
• The role of a hypothesis in a research
study
• Strategies underlying hypothesis
formulation
• The manner to frame your statement of a
hypothesis
2
Research is …….
• Knowledge acquisition gained
– through reasoning
– through intuition
– but most importantly through the use of
appropriate methods
The Scientific Method
Polgar, Thomas 3
Basic Elements of the Scientific
Method
• Empiricism: the notion that enquiry is
conducted through observation and knowledge
verified through evidence
• Determinism: the notion that events occur
according to regular laws and causes. The goal
of research is to discover these
• Scepticism: the notion that any proposition is
open to analysis and critique
Polgar, Thomas 4
Scientific Method
1. Choose a question to investigate
2. Identify a hypothesis related to the question
3. Make testable predictions in the hypothesis
4. Design an experiment to answer hypothesis
question
5. Collect data in experiment
6. Determine results and assess their validity
7. Determine if results support or refute your
hypothesis
5
The Scientific Method
1. Suspicion that a factor (exposure)
may influence occurrence of disease or
a noted health outcome
- Observations in clinical practice
- Examination of disease/outcome patterns
- Do subpopulations have higher or lower rates?
- Are disease rates increased in the presence of certain
factors?
- Observations in laboratory research
- Theoretical speculation
6
The Scientific Method
2. Identify variables you are interested in:
• Exposure - (risk factor, protective factor,
predictor variable, treatment)
• Outcome - (disease, event)
3. Formulate a specific hypothesis
- Frame a hypothesis which seeks to
answer a specific question about the
relationship between an exposure and an
outcome 7
Basic Question in Research
Are exposure and disease/outcome linked?
Exposure Disease / Health
Outcome
Is there an association between them?
8
Next Step: Design Study
• Study Designs …(not exhaustive)
– Case series
– Cross-sectional
– Case-control
– Cohort
– Randomized controlled clinical trial
9
Association
• From the results of your study, does a
statistical relationship exist between two
or more events, characteristics, or other
variables
• Is there a statistical relationship, or
association, between exposure and
disease/outcome?
10
Statistical Association
The degree to which the rate of disease
or outcome in persons with a specific
exposure is either higher or lower than the
rate of disease or outcome among those
without that exposure.
11
The Scientific Method
Assess validity of association
- Does the observed association really exist?
- Is the association valid?
- Are there alternative explanations for the
association?
- Chance
- Bias
- Confounding
12
Hypotheses
Shape and guide a research study in
terms of:
• identification of study sample size
• what issues should be involved in
data collection
• the proper analysis of the data
• data interpretation
13
Hypothesis Formulation
--- Formulate a hypothesis
--- Frame the hypothesis in
a format that is testable
--- Test the hypothesis
14
Hypothesis Formulation
• Observations from:
–Literature (review PubMed on topic area)
–Natural experiments (e.g. migrant studies)
–Multi-national comparisons
–Descriptive studies (assessment of person,
place, and time characteristics)
–Creativity
15
16
Cervical
Cancer
• Infectious and chronic diseases show
great variation from one country to
another.
• Some differences may be attributed to:
--- Climate
--- Cultural factors
--- Diet
--- Genetics
17
Descriptive Study Designs
Used to help formulate hypotheses
18
Case Series Approach
• Identify the experience of a group of
patients with a similar diagnosis, or
• Identify the experience of a group of
individuals with an exposure in common
– Patients or individuals may be identified
from a single or multiple sources
19
Population Survey Approach
• Describe issues related to disease or
exposure in populations
• Usually rely upon routinely collected data
from established surveillance or notifiable
disease systems
20
Unique Component: usually identify the
characteristics of an issue from a representative
sample of the population
Three essential characteristics
that we look to measure in
descriptive studies are...
•Person
•Place
•Time
21
Person
Since disease not does occur at random:
What kinds of people tend to develop a
particular disease, and who tends to
be spared? What’s unusual about
those people?
22
Person Factors
• Age, gender, race, ethnicity
• Genetic predisposition
• Concurrent disease
• Diet, exercise, smoking
• Risk taking behavior
• SES, education, occupation
23
Place
Since disease not does occur at random:
Where is the disease especially common or
rare, and what is different about those
places?
24
Place Factors
• Geographic place
– residence
– occupation
– climate
– geology
– population density
– economic development
– nutritional practices
– medical practices 25
Time
Since disease not does occur at random:
How does disease frequency change over
time, and what other factors are
temporally associated with those changes?
26
Time Factors
• Calendar Time / Time of Day
• Time since an event
• Date of onset
• Age (time since birth in the young)
• Seasonality
• Temporal trends
27
Remember the Elements of the
Scientific Method
Discoveries or hypotheses are sometimes
resisted because they seem counter-intuitive
28
Hypothesis Framing
Traditionally…..
H0: “Null” hypothesis (assumed)
H1: “Alternative” hypothesis
29
Case Series (in practice)
• Description of clinical/epidemiologic
characteristics of a number of patients
with a given disease
- usually a consecutive set of clinical
cases of disease (or health issue)
• Analyze cases together to learn about
the disease (be careful as results do not
demonstrate temporal relationships)
30
Mandil
H0: There is no association between the
exposure and disease of interest
H1: There is an association between the
exposure and disease of interest
(beyond what might be expected
from random error alone)
31
Hypothesis Framing
Another Type of Framing:
What is the best estimate of the risk of disease
in those who are exposed compared to those
who are unexposed (i.e. exposed are at XX
times higher risk of disease).
This moves away from the simple dichotomy of
yes or no for an exposure/disease association –
to the estimated magnitude of effect irrespective
of whether it differs from the null hypothesis.
32
Hypothesis Framing
Ways to Express Hypotheses:
1. Suggest possible events…
The rate of survival will
increase after surgery.
33
Hypothesis Framing
Ways to Express Hypotheses:
2. Suggest relationship between specific
exposure and health-related event…
A high cholesterol intake is associated
with the development (risk) of coronary
heart disease.
34
Hypothesis Framing
Ways to Express Hypotheses:
3. Suggest cause-effect relationship….
Cigarette smoking is a cause of
lung cancer
35
Hypothesis Framing
Ways to Express Hypotheses:
4. “One-sided” vs. “Two-sided”
One-sided example:
Helicobacter pylori infection is associated
with increased risk of stomach ulcer
Two-sided example:
Weight-lifting is associated with risk of
lower back injury 36
Hypothesis Framing
Guidelines for Framing Hypotheses:
1. State the exposure to be measured as
specifically as possible.
2. State the health outcome as
specifically as possible.
Strive to explain the smallest amount of
ignorance
37
Hypothesis Framing
Example Hypotheses:
POOR
Eating junk food is associated with the
development of cancer.
GOOD
The human papilloma virus (HPV)
subtype 16 is associated with the
development of cervical cancer.
38
Hypothesis Framing
The Next Step
• Formally test the identified hypotheses in a
research study
• The study should follow a specific plan
or protocol (the study design)
• Study designs direct how the
investigation is conducted and allows for
the translation of a conceptual hypothesis
into an operational one
39
Mandil
Newton
“Disappointment is
when a beautiful
hypothesis is
destroyed by an
ugly fact”
40

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Research Techniques.ppt

  • 1. Thomas Songer, PhD Introduction to Research Methods In the Internet Era Scientific Method Identifying Hypotheses Introduction to Research
  • 2. Key Lecture Concepts • Understanding the process described as “the scientific method” • The role of a hypothesis in a research study • Strategies underlying hypothesis formulation • The manner to frame your statement of a hypothesis 2
  • 3. Research is ……. • Knowledge acquisition gained – through reasoning – through intuition – but most importantly through the use of appropriate methods The Scientific Method Polgar, Thomas 3
  • 4. Basic Elements of the Scientific Method • Empiricism: the notion that enquiry is conducted through observation and knowledge verified through evidence • Determinism: the notion that events occur according to regular laws and causes. The goal of research is to discover these • Scepticism: the notion that any proposition is open to analysis and critique Polgar, Thomas 4
  • 5. Scientific Method 1. Choose a question to investigate 2. Identify a hypothesis related to the question 3. Make testable predictions in the hypothesis 4. Design an experiment to answer hypothesis question 5. Collect data in experiment 6. Determine results and assess their validity 7. Determine if results support or refute your hypothesis 5
  • 6. The Scientific Method 1. Suspicion that a factor (exposure) may influence occurrence of disease or a noted health outcome - Observations in clinical practice - Examination of disease/outcome patterns - Do subpopulations have higher or lower rates? - Are disease rates increased in the presence of certain factors? - Observations in laboratory research - Theoretical speculation 6
  • 7. The Scientific Method 2. Identify variables you are interested in: • Exposure - (risk factor, protective factor, predictor variable, treatment) • Outcome - (disease, event) 3. Formulate a specific hypothesis - Frame a hypothesis which seeks to answer a specific question about the relationship between an exposure and an outcome 7
  • 8. Basic Question in Research Are exposure and disease/outcome linked? Exposure Disease / Health Outcome Is there an association between them? 8
  • 9. Next Step: Design Study • Study Designs …(not exhaustive) – Case series – Cross-sectional – Case-control – Cohort – Randomized controlled clinical trial 9
  • 10. Association • From the results of your study, does a statistical relationship exist between two or more events, characteristics, or other variables • Is there a statistical relationship, or association, between exposure and disease/outcome? 10
  • 11. Statistical Association The degree to which the rate of disease or outcome in persons with a specific exposure is either higher or lower than the rate of disease or outcome among those without that exposure. 11
  • 12. The Scientific Method Assess validity of association - Does the observed association really exist? - Is the association valid? - Are there alternative explanations for the association? - Chance - Bias - Confounding 12
  • 13. Hypotheses Shape and guide a research study in terms of: • identification of study sample size • what issues should be involved in data collection • the proper analysis of the data • data interpretation 13
  • 14. Hypothesis Formulation --- Formulate a hypothesis --- Frame the hypothesis in a format that is testable --- Test the hypothesis 14
  • 15. Hypothesis Formulation • Observations from: –Literature (review PubMed on topic area) –Natural experiments (e.g. migrant studies) –Multi-national comparisons –Descriptive studies (assessment of person, place, and time characteristics) –Creativity 15
  • 17. • Infectious and chronic diseases show great variation from one country to another. • Some differences may be attributed to: --- Climate --- Cultural factors --- Diet --- Genetics 17
  • 18. Descriptive Study Designs Used to help formulate hypotheses 18
  • 19. Case Series Approach • Identify the experience of a group of patients with a similar diagnosis, or • Identify the experience of a group of individuals with an exposure in common – Patients or individuals may be identified from a single or multiple sources 19
  • 20. Population Survey Approach • Describe issues related to disease or exposure in populations • Usually rely upon routinely collected data from established surveillance or notifiable disease systems 20 Unique Component: usually identify the characteristics of an issue from a representative sample of the population
  • 21. Three essential characteristics that we look to measure in descriptive studies are... •Person •Place •Time 21
  • 22. Person Since disease not does occur at random: What kinds of people tend to develop a particular disease, and who tends to be spared? What’s unusual about those people? 22
  • 23. Person Factors • Age, gender, race, ethnicity • Genetic predisposition • Concurrent disease • Diet, exercise, smoking • Risk taking behavior • SES, education, occupation 23
  • 24. Place Since disease not does occur at random: Where is the disease especially common or rare, and what is different about those places? 24
  • 25. Place Factors • Geographic place – residence – occupation – climate – geology – population density – economic development – nutritional practices – medical practices 25
  • 26. Time Since disease not does occur at random: How does disease frequency change over time, and what other factors are temporally associated with those changes? 26
  • 27. Time Factors • Calendar Time / Time of Day • Time since an event • Date of onset • Age (time since birth in the young) • Seasonality • Temporal trends 27
  • 28. Remember the Elements of the Scientific Method Discoveries or hypotheses are sometimes resisted because they seem counter-intuitive 28
  • 29. Hypothesis Framing Traditionally….. H0: “Null” hypothesis (assumed) H1: “Alternative” hypothesis 29
  • 30. Case Series (in practice) • Description of clinical/epidemiologic characteristics of a number of patients with a given disease - usually a consecutive set of clinical cases of disease (or health issue) • Analyze cases together to learn about the disease (be careful as results do not demonstrate temporal relationships) 30 Mandil
  • 31. H0: There is no association between the exposure and disease of interest H1: There is an association between the exposure and disease of interest (beyond what might be expected from random error alone) 31 Hypothesis Framing
  • 32. Another Type of Framing: What is the best estimate of the risk of disease in those who are exposed compared to those who are unexposed (i.e. exposed are at XX times higher risk of disease). This moves away from the simple dichotomy of yes or no for an exposure/disease association – to the estimated magnitude of effect irrespective of whether it differs from the null hypothesis. 32 Hypothesis Framing
  • 33. Ways to Express Hypotheses: 1. Suggest possible events… The rate of survival will increase after surgery. 33 Hypothesis Framing
  • 34. Ways to Express Hypotheses: 2. Suggest relationship between specific exposure and health-related event… A high cholesterol intake is associated with the development (risk) of coronary heart disease. 34 Hypothesis Framing
  • 35. Ways to Express Hypotheses: 3. Suggest cause-effect relationship…. Cigarette smoking is a cause of lung cancer 35 Hypothesis Framing
  • 36. Ways to Express Hypotheses: 4. “One-sided” vs. “Two-sided” One-sided example: Helicobacter pylori infection is associated with increased risk of stomach ulcer Two-sided example: Weight-lifting is associated with risk of lower back injury 36 Hypothesis Framing
  • 37. Guidelines for Framing Hypotheses: 1. State the exposure to be measured as specifically as possible. 2. State the health outcome as specifically as possible. Strive to explain the smallest amount of ignorance 37 Hypothesis Framing
  • 38. Example Hypotheses: POOR Eating junk food is associated with the development of cancer. GOOD The human papilloma virus (HPV) subtype 16 is associated with the development of cervical cancer. 38 Hypothesis Framing
  • 39. The Next Step • Formally test the identified hypotheses in a research study • The study should follow a specific plan or protocol (the study design) • Study designs direct how the investigation is conducted and allows for the translation of a conceptual hypothesis into an operational one 39 Mandil
  • 40. Newton “Disappointment is when a beautiful hypothesis is destroyed by an ugly fact” 40