The role of study design in addressing potential bias(es)

Question 1

Clinical studies require you to balance what three competing priorities

Answer 1

1) design + conduct a study that provides the correct answer
2) maximise the efficient use of resources
3) comply with ethical, legal, constitutional + professional regulations.

Question 2

what are the 4 sources of potential bias

Answer 2

1) sampling/ selection bias
2) measurement bias
3) analytical bias
4) dissemination bias

Question 3

what are the specific types of sampling bias

Answer 3

• external validity- non representative samples.

- confounding- selection influences exposure and outcome.

Question 4

what are the specific types of measurement bias

Answer 4

• information bias- extent of information varies across participants.
• observer bias- influenced by prior knowledge/ belief.
• recall/ response/ prestige bias- influenced by prior knowledge or belief.

Question 5

what are the specific types of analytical bias

Answer 5

• loss of follow up= specific participants
• omitted variable- imprecise adjustment for confounding.
• attributional bias- intereptation of causality

Question 6

what are the specific types of dissemination bias

Answer 6

• publication bias- eventful results more likely to be published.

Question 7

define a cross sectional study

Answer 7

• provides evidence of association within a sample.
• snapshot
• retrospective

Question 8

define case control study

Answer 8

• provides evidence of association between sampled
• retrospective
• compares 2 groups one with and one without disease and works back to see what exposures they had

Question 9

define cohort study

Answer 9

• provides evidence of directionality of associations
• prospective study
• analyses 2 group of people and see who develops disease and relates this to the exposure they were faced with.

Question 10

define trial

Answer 10

-provides evidence of causality

Question 11

define met analysis

Answer 11

• Provides evidence of reproducibility/generalisability

Question 12

what is the hierarchy of analytical studies for evidence of effect.

Answer 12

• metanylasis (best)
• trial
• cohort
• case-control
• cross- sectional. (worse)

Question 13

define deductive (analytical) reasoning

Answer 13

theory -> hypothesis -> testing -> observation -> reject/not reject.

Question 14

define inductive (descriptive) reasoning

Answer 14

observation -> pattern -> tentative hypothesis -> theory

Question 15

2 types of inductive studies

Answer 15

case study

cross- sectional

Question 16

what are the subdivision of deductive studies

Answer 16

observational

experimental

Question 17

3 types of observational study (selective sampling)

Answer 17

cross- sectional
case-cohort
cohort

Question 18

1 type os experimental study ( selective exposure)

Answer 18

trial