ch 11 - Reasoning about the design and execution of research

Question 1

scientific method

Answer 1

1. 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

Question 2

positive controls

Answer 2

those that ensure a change in the dependent variable when it is expected

Question 3

negative controls

Answer 3

ensure no change in the dependent variable when no change is expected

Question 4

causal relationship

Answer 4

if change in independent variable always precedes change in dependent variable, and change in dependent variable does not occur in absence of experimental intervention

Question 5

Accuracy

Answer 5

ability of instrument to measure a true value

Question 6

precision

Answer 6

also called reliability, ability of an instrument to read consistently or within a narrow range

Question 7

Randomization

Answer 7

members of a test group randomly selected to go into either a control or sham group, or the test group

Question 8

single-blind experiments

Answer 8

the patient or the assessor is blinded

Question 9

double-blind experiments

Answer 9

investigator, subject and assessor are all blinded

Question 10

binary variables

Answer 10

yes vs. no, better vs. worse

Question 11

continuous variables

Answer 11

amount of weight lost, percent improvement in cardiac output

Question 12

categorical variables

Answer 12

state of residence, socioeconomic status

Question 13

categories of observational studies

Answer 13

cohort studies, cross-sectional studies, case-control studies

Question 14

cohort studies

Answer 14

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

Question 15

cross-sectional studies

Answer 15

attempt to categorize patients into different groups at a single point in time

Question 16

case-control studies

Answer 16

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

Question 17

Hill’s Criteria

Answer 17

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

Question 18

bias

Answer 18

result of flaws in data collection phase of an experimental or observational study

Question 19

confounding

Answer 19

error during analysis; incorrect relationship is characterized in data that may or may not be flawed.

Question 20

selection bias

Answer 20

subjects used for the study are not representative of the target population

Question 21

detection bias

Answer 21

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.

Question 22

Hawthorne effect

Answer 22

also called observational bias; posits that behavior of study participants is altered simply because they recognize that they are being studied

Question 23

confounding variables (confounders)

Answer 23

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

Question 24

four core ethical tenets

Answer 24

beneficence, nonmaleficence, autonomy (of patients), justice

Question 25

morally relevant differences

Answer 25

those differences between individuals that are considered an appropriate reason to treat them differently (such as age)

Question 26

equipoise

Answer 26

in studies comparing two potential treatment options, one cannot approach the research with the knowledge that one treatment is superior to the other

Question 27

population

Answer 27

complete group of every individual that satisfies the attributes of interest

Question 28

parameter

Answer 28

information that is calculated using every person in a population

Question 29

sample

Answer 29

any group taken from a population that does not include all individuals from the population

Question 30

internal validity

Answer 30

support for causality

Question 31

external validity

Answer 31

also called generalizability; high generalizability means study has sample that represents the target population

Question 32

statistical significance

Answer 32

not the result of random chance

Question 33

clinical significance

Answer 33

notable or worthwhile change in health status as a result of our intervention