RESEARCH Qs AND METHODS Flashcards
What are determinants of health also known as?
Exposure, treatment and the X part in statistical model
What are ‘health related states and events’ also called?
Outcome, Disease (even substance abuse) and the Y part in a statistical model
What are examples of determinants of health?
Alcohol consumption, smoking, diet and nutrition, mobile phone use, strokes, heart attack, diabetes, mental illness.
What are the two types of epidemiology?
Descriptive and Analytical
What is descriptive epidemiology?
Hypothesis generation. (person-who gets the disease, place- Where?, time- temporal (range from hours to decades) )
What is analytical epidemiology?
Hypothesis TESTING. -study design and methods
What is an example of a hypothesis with helmets and bike riders?
Exposure to wearing a helmet is associated with a decreased risk of dying from a head trauma in a motorcycle accident
What 5 things should a good epidemiologic exposure variable have?
- Have an impact on health
- Be measurable
- Differentiate populations
- Generate testable hypotheses
- Help to prevent or control disease
What qualities should a disease have to make it worthwhile to investigate?
SOME PUBLIC HEALTH SIGNIFICANCE
- number of individuals it affects (current disease status, prevalence)
- types of populations it affects
- causal pathway or risk characteristics
What are the sources of epidemiological hypotheses?
- Individual cases
- Case series
- Descriptive epidemiology finding
- Data dredging or mining
- Lab/animal studies
- Analogies to other exposure outcome relationships
- Common sense
- Luck or chance
- Other epidemiologists and publications
Where do you find an epidemiological hypothesis?
- Read and understand the literature
- Examine descriptive epidemiology data
- Listen to patients and families
- Listen to clinicians
- Read newspaper/watch TV
What issues do you need to consider when embarking in research?
Etiology (cause) of chronic disease often difficult to determine
- Many exposures cause MORE THAN ONE OUTCOME
- Outcomes may be due to MULTIPLE EXPOSURES or continual exposure over time
- Causes may DIFFER BY INDIVIDUAL (not everyone who smokes gets lung cancer)
Does epidemiology determine the cause of a disease in a given individual?
NO!! It determines the RELATIONSHIP or ASSOCIATION between a given exposure and frequency of disease in populations.
Is causation inferred?
YES!! Causation is INFERRED based upon the association and several other factors
How can we measure exposures?
- Questionnaires (asked by researcher, can asses specific constructs - mood assessment)
- Biological (lab tests for blood and urine-recent, and hair for long term))
- Radiological (x-rays, echo)
- Physical examination (height, weight)
- Evaluation of previous medical records
- Sampling of environmental factors
- Biomarkers, genetic markers
What are the two types of error?
Systematic error (bias) and random error (imprecision)
What is the measured score?
‘True’ score +- Error
What is bias?
” Systematic error or deviation from the truth in results or inferences”
- Difference between results and population value due to incorrect measurements being taken or measurements being taken on a non representative sample
What is confounding?
Means “ to mix together” Situation in which a non-causal association between a given association is observed due to the influence of a third variable.
What is an example of confounding?
If study comes out saying “coffee drinkers are more likely to get heart disease than non-coffee drinkers” Then people conclude that coffee CAUSES heart disease…BUT the association between drinking coffee and heart disease can be CONFOUNDED (i.e. there could be another factor contributing to heart disease).
What is the difference between bias and confounding?
Bias creates association that is NOT true, and confounding describes an association that is true but potentially misleading.
WHEN do you control for confounding?
In the DESIGN STAGE and the ANALYSIS STAGE (before you start researching)
HOW do you control for confounding in the DESIGN STAGE? (3 things)
By randomisation (equal distribution of groups) , Restriction (only non smokers, or males for example), and Matching (match for age, sex, social class in case control study- but it is time consuming and expensive)
How do you control for confounding in the ANALYSIS STAGE?
Stratification (two tables of exposure vs. outcome, one for each level of confounder)
- Statistical modelling (can adjust for multiple things- e.g. late antenatal carer by aboriginal infant + 9 risk factors)
What is reliability in the general sense?
Tools that measure a given variable accurately and consistently
What is test-retest reliability?
Test results are consistent over time by administering the same test TWICE over a period of time to a group of individuals.
What is an example of test-retest reliability?
A test designed to asses student learning where it is given to students twice with the second test being given one week after the first
What is inter-rater test reliability?
Assess the degree to which different judges or raters agree in their assessment decision.
What is an example of inter-rater reliability?
Interview panel or an objective structured clinical examination (OSCE)
What is validity?
Legitimacy of the research and its conclusions (measuring what it is supposed to measure) -e.g. making students sit a physics exam to test IQ who have not done physics before.
What is internal validity?
Are results correct for the group being studied? Testing whether results have no confounds. e.g. to test whether people thought they learnt better on the red or green writing would mean that the content (confounder) of the gossip and chem paper has to be the same. -not good
What is external validity?
Are your results gereralisable? Can it be applied to the real world?
What is construct validity?
Does your test measure what it claims to be measuring?
