Definitions

Question 1

What is a Census?

Answer 1

Simultaneous recording of demographic data to all persons in a defined area

Question 2

What is the Crude birth rate?

Answer 2

Number of live births per 1000 population

Question 3

What is the General birth rate?

Answer 3

Number of live births per 1000 fertile women between age of 15-44

Question 4

What is the Total period fertility rate?

Answer 4

Average number of children born to a hypothetical women in her lifetime

Question 5

What is an Incidence rate?

Answer 5

The number of new cases of the disease per 1000 people per year (or 1000 person–years)

Question 6

What is Prevalence?

Answer 6

The amount of people who currently have the disease in a set population (with no time frame)

Question 7

What is Incidence rate ratio?

Answer 7

Incidence rates of two separate populations, with varying exposure, can be compared to see if exposure causes certain diseases

Question 8

What is a confounder?

Answer 8

Something that is associated with both the outcome and the exposure of interest, but is not on the causal pathway

Question 9

What is Standardised mortality rate?

Answer 9

The number of observed deaths / Number of expected deaths x 100

Question 10

What is Variation?

Answer 10

A difference between the ‘observed’ and the ‘actual’ value

Question 11

What is the lower confidence interval?

Answer 11

value ÷ error factor

Question 12

What is the upper confidence interval?

Answer 12

value x error factor

Question 13

What is the P value?

Answer 13

States how likely the results in the study would have occurred by chance if the null hypothesis was true.

Question 14

What is Bias?

Answer 14

Deviation of the results from the truth via certain processes

Question 15

What is Selection bias?

Answer 15

Error due to systematic differences in the ways in which the two groups were collected

Question 16

What is Information bias?

Answer 16

Error due to systematic misclassification of subjects in the group

Question 17

What are the 2 types of Selection bias?

Answer 17

Allocation bias

Healthy worker effect

Question 18

What are the 2 types of Information bias?

Answer 18

Recall bias

Publication bias

Question 19

What is a Cohort study?

Answer 19

Recruiting disease free individuals and classifying them according to their exposure status. Followed up for extended periods, disease progress is monitored, and incidence rates are calculated

Question 20

What is Internal comparison?

Answer 20

Have sub-cohorts within your original group and then compare exposed and unexposed within the cohort. Uses IRR

Question 21

What is external comparison?

Answer 21

Have your exposed population compared against a reference population instead. Uses SMR

Question 22

What is the Healthy worker effect?

Answer 22

Employed individuals are more likely to be healthy than unemployed individuals as they work

Question 23

What is a Case control study?

Answer 23

Recruit disease-free (controls) individuals and diseased individuals (cases) and then exposure status is determined

Question 24

What is Double blinding?

Answer 24

Patient and doctor don’t which treatment they are on, removing any selection bias

Question 25

What is the Bradford Hill criteria?

Answer 25

``` Strength of association Specificity of association Consistency of association Temporal sequence Dose response Reversibility Biological plausibility Coherence of theory Analogy ```

Question 26

What is Clinical equipoise?

Answer 26

Reasonable uncertainty into which drug is better for the patient, so not subjecting patients to known less effective treatment

Question 27

What is Ethical recruitment?

Answer 27

Recruitment for region where drug will take affect and no unethical exclusions from the trial

Question 28

What is Valid consent?

Answer 28

Participants given sufficient knowledge, cooling off period, chance to ask questions, and ability to withdraw from trial at any point

Question 29

What is Voluntariness?

Answer 29

No coercion or manipulation into entering the trial

Question 30

What is a Systematic review?

Answer 30

A compilation of primary studies

Question 31

What is a Meta analysis?

Answer 31

Provide quantitative synthesis of the primary studies used in the trial

Question 32

What is the Fixed effects model?

Answer 32

Assumes the studies used are homogenous and any variation between data comes from within-study variation

Question 33

What is the Random effects model?

Answer 33

Assumes the studies are heterogeneous and variation between data comes from within-study variation and between-study variation

Question 34

What is Publication bias?

Answer 34

Studies are only likely to be published if results are statistically significant or have a large sample size. Funnel plots can determine Publication bias

Question 35

How does a Forest plot display information?

Answer 35

Square size linked to weight in study Diamond is overall measurement Tips of diamond represent confidence intervals

Question 36

What does it mean if the null value lies within the 95% CI?

Answer 36

The result may be due to chance, we cannot reject the null hypothesis.

Question 37

What does it mean if the 95% CI excludes the null value?

Answer 37

The association is unlikely to be due just to chance.

Question 38

What is reverse causality?

Answer 38

Possible that the cause-effect relationship exists, but in the opposite direction

Question 39

What is the Henle Koch postulates?

Answer 39

Necessary - cause always precedes disease Sufficient - cause alone leads to disease Specific - cause absent in other diseae

Question 40

Outline steps in RCT

Answer 40

Allocate Follow up Assess Compare

Question 41

What is the placebo effect?

Answer 41

Psychological benefit from being cared for, or differently, and being on a new treatment.

Question 42

What are the types of outcome?

Answer 42

Patho physiological Clinically defined Patient focused

Question 43

What are the features of an ideal outcome?

Answer 43

``` Appropriate/relevant Valid and attributable Sensitive and specific Reliable and robust Simple and sustainable Cheap and timely ```

Question 44

What is an explanatory trial?

Answer 44

An as treated analysis. The non compliers are excluded

Question 45

What is a pragmatic trial?

Answer 45

Intention to treat analysis. Better indication of drug in real life as non compliers are kept in

Question 46

What makes a clinical trial ethical?

Answer 46

Clinical equipoise (not knowing which treatment is better) Scientifically robust Ethical recruitment Valid consent