Lecture 2 (sept 13th)

Question 1

Study Goal vs Objective

Answer 1

Goals are just ideas, objectives are actionable and planning related

Question 2

Theoretical framework

Answer 2

a set of established models in the published literature that can
inform the components and flows of the conceptual framework for a new research study

Question 3

We use models in health research

Answer 3

 To organize our thoughts
 To explore determinant/health relationships in a systematic manner
 As a guide for analysis
 To identify ‘modifiable’ factors for intervention

Question 4

Lalonde’s Model

Answer 4

Title: A New Perspective on the Health of Canadians.
Considered to be first modern government doc in Western
context to propose the health field look beyond the
biomedical health care system.

Question 5

Lalonde model: Proposed health field

Answer 5

= human biology + environment +
lifestyle + health care organization

Question 6

Evans and Stoddart model

Answer 6

See Tutorial 2

Question 7

Eco-social Model/the Big picture
Individual

Answer 7

Sex, age, health, etc.

Question 8

Eco-social Model/the Big picture Microsystem

Answer 8

Family
school
health services
peers
Church community
Neighbourhood play area

Question 9

Exosystem

Answer 9

social welfare services
mass media
legal services
friends of family
neighbours

Question 10

Macrosystem

Answer 10

ideologies of the culture and attitude

Question 11

conceptual model

Answer 11

A model that a researcher sketches using boxes and arrows to illustrate the various relationships
that will

Question 12

Study goal
Objectives
Models
Methods

Answer 12

> ideas
actionable / Plan
a framework
blueprint / instructions

Question 13

Probability Sampling

Answer 13

Involves using selection techniques wherein the probability of selecting
each sampling unit is known

Prob (sampled) = n/N should equal 1

Question 14

Probability Sampling Methods

Answer 14

1. Simple random sampling
2. Stratified random sampling
3. Cluster sampling
4. Multistage sampling

Question 15

Simple Random Sampling

Answer 15

A simple random sample is a randomly selected subset of a population.
ex. 12 out of 36 people randomly
selected

Question 16

Stratified Sampling

Answer 16

Random samples from distinct groups
> Geography (urban, rural, suburban)
> Sex (male, female, other)
Ex. 3 from each stratum
are randomly selected

Question 17

Cluster Sampling

Answer 17

Researchers divide a population into smaller groups known as clusters. They then randomly select among these clusters to form a sample.
> Natural clusters (schools, neighbourhoods)
rather than individual units are selected
> Observation are made on all units within a
cluster
> Cluster sampling of schools
> All eligible children within each school included

Question 18

Multistage Sampling

Answer 18

> Primary sampling units are selected
(e.g. municipalities)
Secondary units selected within
primary units (e.g. individuals)
May have more levels ex:
> Secondary units: city blocks
> Tertiary units: individuals

Question 19

Other Sampling Techniques : Nonprobability-based sample

Answer 19

Convenience Sample:
Purposive sampling:

Question 20

Convenience Sample:

Answer 20

Selection from a nonprobability-based
source population due to ease of access to those individuals,
schools, workplaces, organizations, or communities
> Use with caution
> Often systematically different from the target and source
populations they are intended to represent

Question 21

Purposive sampling:

Answer 21

Recruitment of the participants for a
qualitative study based on the special insights they can provide
(Nov. 15)

Question 22

Key informants

Answer 22

Are individuals selected to participate in a
qualitative study because they have expertise relevant to the
study question
Other Sampling Techniques

Question 23

Errors Associated with Sampling

Answer 23

> Does the sample represent the target
population?
External validity
Sampling bias

Question 24

> Don’t confuse with selection bias (when
healthier or educated people are more likely to
volunteer for research, September 27)

Question 25

Ethical issues in sampling
Vulnerable Populations

Answer 25

Definition: Those who might have limited ability to make an autonomous decision about
volunteering to participate in a research study (more next class on Wednesday)

Question 26

Vulnerable Populations examples

Answer 26

Young children
Some individuals with serious health issues
People in prison and some other socially marginalized populations
Limited ability to make an independent decision about volunteering because of other reasons

Question 27

Vulnerable populations

Answer 27

 Should not be selected unless absolutely necessary
 At the same time, systematically exclusion is also unethical
 Their health issues should be studied
 Extra consideration of the potential risks of research to participants (stricter ethical
considerations)

Question 28

The Importance of Sample Size

Answer 28

We want to recruit just the right number of participants
 Recruiting too many participants wastes resources
 Recruiting too few participants makes the study invalid
The desired sample size (the number of observations in a data set) for a quantitative study
is based on statistical estimations about how many data points are required in order to
answer the study question with a specified level of certainty

Question 29

Proper Sample Size can be Calculated Based on

Answer 29

The effect estimate of exposure on the outcome:

The amount of errors we can accept

Variation of the outcome in the population

Question 30

The effect estimate of exposure on the outcome:

Answer 30

For larger effect smaller sample is required

Question 31

The amount of euro(s) we can accept

Answer 31

For smaller desired error larger sample is
required

Question 32

Variation of the outcome in the population

Answer 32

Complex, largest when prevalence is 50%

Question 33

Type 2 error (β)

Answer 33

False negative
You’re not pregnant when you actually are.

Question 33

Type one error (α)

Answer 33

False positive
example : you’re pregnant and you’re actually not

Question 34

Type 1 error (α) occurs when

Answer 34

A study population yields a
statistically-significant test result even though a significant difference or association does not actually exist in the source population

Question 35

Type 2 error (β) occurs when

Answer 35

A statistical test of data from
research finds no significant result even though a
significant difference or association actually exists in the source population

Question 36

Amount of random α and β errors is

Answer 36

a function of sample size

Question 37

(1- β) is usually referred as the

Answer 37

The power of the study, i.e. how much the study is able to detect a
true relationship, can be calculated post hoc (after the study is complete

Question 38

Data Collection in Health Often (NOT ALWAYS) is conducted by

Answer 38

interviewing (either self or by an interviewers) participants via questionnaires or survey instrument

Question 39

Other methods of Data Collection in Health:

Answer 39

 Direct measurement of physical functioning (measurement of height, weight,
blood pressure)
 Blood work (measurement of hormones, sugar)
 Sampling other tissues
 Imaging (X-ray, CT scan, MRI)

Question 40

Interview is …

Answer 40

…the process of verbally asking a participant questions and recording that
person’s responses
Trained interviewers record the responses, and they can ensure the accuracy and
completeness of each questionnaire
Interviews may require major time commitments from study personnel

Question 41

Self-administered survey

Answer 41

is a questionnaire form that participants complete
by themselves, using either a paper-and-pencil version or online

Question 42

In-depth Interview for Qualitative
Studies

Answer 42

Spending 1 or 2 hours interviewing a key informant (not sampled) using open-ended questions
> semi-structured interview
>Probing

Question 43

In a semi-structured interview

Answer 43

the interviewer starts with a list of open-ended
questions that will be asked of each participant, but these questions or lists of topics
are merely starting points for eliciting responses from participant

Question 44

Probing

Answer 44

Is an interviewing technique that prompts an interviewee to provide a more complete or specific response
Used in qualitative studies
specifically interviews

Question 45

Interviewers can also record their observations

Answer 45

of the body language and other
nonverbal communication conveyed by interviewee

Question 46

Interview pros and cons

Answer 46

Pros: we can train interviewers to ensure the accuracy and
completeness of each questionnaire

Cons: may require major time
commitments, expensive

Question 47

Self-administered survey pros and cons

Answer 47

Pros: cost- and time-efficient
Possibly of approaching a large number of participants
The best way to get honest answers to sensitive questions
Cons: Problematic for low literacy populations, and those
who have limited Internet access or be unfamiliar with
computers
page 184 of the textbook

Question 48

Training Interviewers

Answer 48

> Standard protocols will be followed to ensure the interview process is
the same for all study participants
All interviewers should undergo role-specific training and have an
opportunity to practice their interview skills, pilot testing, quality control to avoid interviewer bias

Question 49

Interviewer bias

Answer 49

Occurs when interviewers systematically question cases and controls or exposed and
unexposed members of a study population differently, such as probing only individuals they believe to
have the disease or exposure of interest for more information

Question 50

Uniformity

Answer 50

is easiest to accomplish when all interviewers are
provided with the tools they need to follow a standardized set of procedures

Question 51

Questionnaire

Answer 51

A series of questions used as a tool for systematically gathering data from
study participants

Question 52

Systematically Gathering Data for Focused and specific content steps (3)

Answer 52

1) List the topics that the survey instrument must cover
Theoretical frameworks can inform the diversity of questions that may be relevant
to include in the survey instrument
2) The first set of questionnaire items typically are ones that enable the
researcher to confirm that participants meet the eligibility criteria for the
study, exclude ineligible people
3) Several questions may be required in order to accurately assign participants to
key exposure and disease categories

Question 53

Types of questions

Answer 53

Closed-ended questions
Open-ended questions

Question 54

Open-ended questions

Answer 54

(also called free response questions) allow an unlimited
number of possible response

Question 55

Closed-ended questions

Answer 55

allow a limited number of possible responses
> Date and time questions
> Numeric questions
> Categorical
> Ranked (ordinal) categorical answers have an inherent order
> Unordered (nominal) categorical answers do not have any built-in order
> Paired comparisons

Question 56

Practical Considerations for questionnaires

Answer 56

1) Order of questions
2) Getting the correct answer
3) Data recording method
4) Layout and formatting
5) Back translation

Question 57

1) Order of questions

Answer 57

> It is better to start with easy or at least general questions before moving to more
difficult or sensitive questions
It is often best to group similar questions with similar response types, so that
they are asked consecutively

Question 58

2) Getting the correct answer

Answer 58

 Sometimes it is better to mix up such questions to prevent habituation, an error that occurs when
participants become so accustomed to giving a particular response (like “agree… agree… agree…”) that
they continue to reply with the same response even when that does not match their true perspectives
 Survey developers must carefully consider how previous questions could taint the answers to later ones