Chapter 2 - Evaluating Health Claims

scientific method
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Terms in this set (24)
scientific method
used to find experimental evidence
what is a blind experiment?
when they use a placebo
What are methods of producing valid experimental results?
large sample sizes, a blind experiment (placebo), double blind, crossover
what are the different types of evidence?
experimental, epidemiological, clinical, personal, anecdotal
How to find experimental evidence?
1. test hypothesis
2. compare control w experimental group
3. compare a group that does both control & experimental
Experiment procedure in testing treatments:
1. randomly select a sample from the population
2. randomly assign a control group and experimental group(s)
3. control gets a placebo (blind) or no treatment, experimental receives treatment(s)
4. measure outcomes
5. analyze statistics
6. interpret results
7. communicate results
How big should sample be?
depends on:
- variability of measured value in population
- expected size of treatment effect
- possibility of negative side effects & expected size of this effect compared to population
Is bigger sample size better?
depends on question & cost-benefit analysis
What is a benefit of double blind experiments?
reduces the effects of bias
What is the advantage of a crossover experiment?
you eliminate the effect of individual variation between control and experimental bc they are the same
What is the best form of experiment?double blinded randomized cross overProblems with experimentation- time or latency - ethicsalternatives to live animal/human testing:tissue cultures, computer modellingWhat is epidemiology?use of population data without intervention; observation onlyWhat are factors that can allow one to consider an association to be causal?- strength of association - dose-response - consistency - temporally correct - specificity - biological plausibilityEpidemiological exampleJohn Snow proved cholera spreads through contaminated waterWhere does clinical evidence come from?experience of clinicians - physicians, dentists, chiropractors, psychologists, athletic trainers etc.Personal vs Anecdotal?Personal: your own personal experiences vs. anecdotal: story from someone elseHow to know if health information is valid?source? date? author? evidence? bias? logic?Canada's health care system timeline1948: started by premier of Sask. Tommy Douglas 1957: insurance plan for physician services added 1964: fed. gov. pays for part of plan 1972: all provinces joined plan 1985: Medical Care Act replaces Canada Health ActWhat are the 5 principles of the Canada Health Act?- public administration: must be administered on a non-profit basis - comprehensiveness: must cover all insured services provided by hospitals/physicians, dental service in a hospital - universality: residents entitled to any health insurance services provided in their province/territory - portability: if canadian resident moves to another province, old plan covers services until new one is in place - accessibility: access must be provided when and where available, no discrimination of age, health, financesHealth care providersdoctors, nurses, nurse practitionersPatients have the (medical) rights to:- access their records & have them kept private (illegal for them to be accessed outside of Canada) - receive treatment providing a reasonable degree of care - know of potential dangers/benefits of treatment - receive competent diagnosis and treatment - retain control and dignity of person - designate someone to make your decisions if you cannot - informed consentPhysician requirements- graduate from accredited med school & at least 8 years of post secondary - pass an exam administered by the Medical Council of Canada and by each province's medical council - finish an internship w requirements set by College of physicians and surgeons in each province - pay a licence fee to the college of physicians and surgeons