ch 11 - Reasoning about the design and execution of research Flashcards
scientific method
- generate a testable question, 2. gather data and resources, 3. form a hypothesis, 4. collect new data, 5. Analyze the data, 6. Interpret the data, 7. Publish, 8. Verify results
positive controls
those that ensure a change in the dependent variable when it is expected
negative controls
ensure no change in the dependent variable when no change is expected
causal relationship
if change in independent variable always precedes change in dependent variable, and change in dependent variable does not occur in absence of experimental intervention
Accuracy
ability of instrument to measure a true value
precision
also called reliability, ability of an instrument to read consistently or within a narrow range
Randomization
members of a test group randomly selected to go into either a control or sham group, or the test group
single-blind experiments
the patient or the assessor is blinded
double-blind experiments
investigator, subject and assessor are all blinded
binary variables
yes vs. no, better vs. worse
continuous variables
amount of weight lost, percent improvement in cardiac output
categorical variables
state of residence, socioeconomic status
categories of observational studies
cohort studies, cross-sectional studies, case-control studies
cohort studies
observational study in which subjects are sorted into two groups based on differences in risk factors (exposures), and then assessed at various intervals to determine how many subjects in each group had a certain outcome
cross-sectional studies
attempt to categorize patients into different groups at a single point in time
case-control studies
identify the number of subjects with or without a particular outcome, then look backwards to assess how many subjects in each group had exposure to a particular risk factor
Hill’s Criteria
describe components of an observed relationship that increase the likelihood of causality in the relationship; include temporality, strength, dose-response relationship, consistency, plausibility, consideration for alternative explanations, experiment, specificity, and coherence
bias
result of flaws in data collection phase of an experimental or observational study
confounding
error during analysis; incorrect relationship is characterized in data that may or may not be flawed.
selection bias
subjects used for the study are not representative of the target population
detection bias
results from educated professionals using their knowledge in an inconsistent way. finding one variable that prior studies have indicated correlates to another variable increases likelihood that researcher will then search automatically for that second variable.
Hawthorne effect
also called observational bias; posits that behavior of study participants is altered simply because they recognize that they are being studied
confounding variables (confounders)
third party variables in which there is no direct causality between two findings. For ex people may have red hair and be more likely to have lower pain tolerance which could both be caused by a gene mutation but do not have a causal relationship to each other
four core ethical tenets
beneficence, nonmaleficence, autonomy (of patients), justice
