HaDPop

Question 1

Define fecundity

Answer 1

The physical ability to reproduce

Question 2

Define fertility

Answer 2

The realisation of the fecundity (physical ability to reproduce) as actual births

Question 3

What is the crude birth rate defined as?

Answer 3

The number of live births per thousand people in a population

Question 4

What is the general fertility rate defined as?

Answer 4

The number of live births per 1000 of the populations women who are ages 15-44

Question 5

What do we mean when we say the total period fertility rate?

Answer 5

All of the age specific fertility rates together

Question 6

What is the crude death rate defined as?

Answer 6

The amounts of deaths per 1000 people in a population

Question 7

What is the age-specific death rate defined as?

Answer 7

The amount of deaths per 1000 people in an age group per year

Question 8

What does SMR stand for?

Answer 8

Standardised mortality ratio

Question 9

What is the point of using an SMR?

Answer 9

It adjusts for age and sex distribution which removes confounding

Question 10

How does an SMR work? i.e. think of how it is calculated

Answer 10

It works by comparing a population being studied to a reference population, any values of 100 show no difference

Observed pop./Expected pop. (x100)

Question 11

Define Census

Answer 11

The simultaneous recording of demographic data at a particular time pertaining to all individuals who live in a particular territory

Question 12

How is an incidence rate worked out? (NOT HOW IS AN INCIDENCE RATE RATIO WORKED OUT)

Answer 12

Incidence rates are worked out by how many new events of something happen in a population over time. Therefore:

Incidence rate = New Events ÷ (Population x Time)

Question 13

How is an incidence rate ratio worked out?

Answer 13

One incidence rate divided by another

Question 14

Define incidence rate

Answer 14

The number of new cases of a disease in a population over a period of time

Question 15

How would you work out the two confidence limits?

Answer 15

Error factor x IR

IR ÷ Error Factor

Question 16

Can you ever accept the null hypothesis?

Answer 16

NO!

You can only ever reject or not reject the null hypothesis.

Question 17

Define Prevalence

Answer 17

The number of existing cases of a disease in a population

Question 18

What is a confounding factor?

Answer 18

A confounding factor is any factor that links the exposure with the outcome but is not on the causative pathway

Question 19

Allocation bias is a form of which type of bias?

Answer 19

Selection bias

Question 20

Recall bias ia form of which type of bias?

Answer 20

Information bias

Question 21

What type of plot can be used to identify publication bias? What does it do?

Answer 21

Funnel plot which shows whether there are unpublished results omitted

Question 22

What is the healthy worker effect? What type of bias is it?

Answer 22

The healthy worker effect is a form of selection bias that occurs when populations who are in work are being to compared to just the general population

Question 23

What is the main difference between internal and external cohort studies?

Answer 23

External cohort studies use a reference population whereas an internal cohort study is done with different sub groups

Question 24

What is a cohort study?

Answer 24

Where you look at people who have been exposed and people that have been unexposed then you wait to see who has developed the disease

Question 25

Why is a cohort study useful?

Answer 25

- It can be used for looking into a lot of different outcomes of an exposure - It is useful for rare exposures but not rare diseases

Question 26

Why is a cohort study not that useful?

Answer 26

- Expensive | - Time consuming

Question 27

What is a retrospective cohort study?

Answer 27

A cohort study where disease free individuals are recruited and their exposure status is recorded from historical documentation and they are followed up

Question 28

What is a prospective cohort study?

Answer 28

A cohort study where disease free individuals are recruited, their exposure status determined after they have been recruited and they are then followed up

Question 29

What is a case control study?

Answer 29

A study looking into people who are ill and a group of healthy people working backwards to determine an exposure

Question 30

Why is a case control study useful?

Answer 30

- Cheap - Quick - Useful for rare diseases but not rare exposures

Question 31

Why is a case control study not that useful?

Answer 31

- Prone to recall bias | - Prone to selection bias

Question 32

How is an odds ratio worked out?

Answer 32

(Exposed cases ÷ Unexposed cases) ÷ (Exposed controls ÷ unexposed controls)

Question 33

How can you reduce the error factor of an odds ratio?

Answer 33

Increasing controls

Question 34

What are the three main steps to a randomised control trial?

Answer 34

- Identify patients - Randomly allocate participants - Follow up participants identically

Question 35

Why is double blinding often used?

Answer 35

- Removes the placebo effect | - Removes selection bias

Question 36

What is the intention to treat model?

Answer 36

The idea that even if people don't keep using the treatment correctly/drop out they should still be included

Question 37

List the Bradford Hill Criteria and briefly describe what it means? 9 points (Eurgh...I want to die)

Answer 37

- Strength of association is how much difference is observed i.e. a high IRR - Specificity of association is how specific the disease/exposure is i.e. cancer is a very broad group - Temporal sequence is asking whether the disease precedes the exposure i.e. a nested case control study - Dose response is how much you give compare to how much difference it makes - Reversibility can you reverse the effect you are having - Biological plausibility does it have a mechanism that makes sense - Coherence of theory confirms current thinking about things - Analogy similar disease have similar outcomes - Consistency means that the results can be replicated again by other people

Question 38

How would you minimise losses and increase compliance?

Answer 38

- Minimise losses by honesty and make clear, accessible follow up - Compliance by making it easy to use and allowing patients to ask questions

Question 39

What 3 ways could you ensure a randomised control trial was ethical?

Answer 39

- Clinical equipose (no idea which is better) - Scientifically robust (for the good of the science) - Use volunteers

Question 40

What 3 features should a study have to be included in a systematic review?

Answer 40

- Transparent - Replicable - Explicit

Question 41

How is the data from a meta-analysis displayed? What is shown and how?

Answer 41

Shown via forest plots: - Odds ratios as squares where weighting given is size of square - Pooled estimates are diamonds with 95% confidence limits

Question 42

What does the fixed effects model assume?

Answer 42

It assumes that studies are homogenous and that any data variation comes from within the study

Question 43

What does the random effects model assume?

Answer 43

Assumes that the studies are heterogenous and that variation comes from between the studies as well

Question 44

What will a well balanced study show in a funnel plot?

Answer 44

A well balanced study will show a funnel shape

Question 45

What are the advantages of using a systematic review?

Answer 45

- Reduce bias and exclude shit studies - Give an overall figure for multiple studies - Used in evidence based guidelines