HaDPop Glossary

Question 1

Census

Answer 1

The simultaneous recording of demographic data by the government at a particular time pertaining to all persons who live in a particular territory

Question 2

Crude birth rate

Answer 2

The number of live births per 1,000 population in a given year

Question 3

General fertility rate

Answer 3

The number of live births per 1,000 women aged 15-44 year olds in a given year

Question 4

Total fertility rate (TFR)

Answer 4

The average number of children that would be born to a hypothetical woman in her life

Question 5

Crude death rate

Answer 5

The number of deaths per 1,000 in a given year

Question 6

Age-specific death rate

Answer 6

The number of deaths per 1,000 in a specific age range in a given year

Question 7

Standard mortality ratio

Answer 7

Compares numbers of observed and expected deaths is age-sex distributions in a population were identical

Question 8

Incidence

Answer 8

The number of new cases of a disease in a given time period

The tap

Question 9

Prevalence

Answer 9

The number of people affected by a disease - no time period; NOT A RATE (the bath tub)

Prevalence = incidence x length of disease

P = I x L

Question 10

Incidence rate

Answer 10

(number of new cases) / (population x time)

Normal unit = people-years

Question 11

Incidence rate ratio

Answer 11

(Exposed incidence rate) / (not exposed incidence rate)

Question 12

Absolute risk

Answer 12

Absolute risk measures the size of a risk in a person or group of people (Eg absolute risk of an individual developing Alzheimer’s as they age)

Question 13

Relative risk

Answer 13

Relative risk compares a risk in two different groups of people

Eg Relative risk of diabetes between obese and normal weighted people

Question 14

Confounding factor

Answer 14

A factor which is associated to both disease of interest and the exposure of interest without being part of the causal pathway

Question 15

Confidence interval

Answer 15

A range of values so defined that there is a specified probability that the true value of a parameter lies within it (Eg 95%)

Question 16

Statistical significance

Answer 16

If the results of a test have statistical significance, it means that they are not likely to have occurred by chance alone. In such cases, we can be more confident that we are observing a ‘true’ result

Question 17

Cohort study

Answer 17

This study follows a people over a period of time to see how their exposure affects their outcome,

Starts with OUTCOME FREE individuals

Question 18

Survival bias

Answer 18

The logical error of only concentrating on those who survived a situation, and overlooking those who didn’t. Can result in false conclusions being drawn

Question 19

Observational study

Answer 19

A study where the exposure cannot be varied. Instead people are just observed

Question 20

Odds ratio

Answer 20

Odds ratio compare the odds of an outcome in an exposed group compared to an unexposed group

Question 21

Case-control study

Answer 21

The study compares a group of people with a condition with a group who do not, the study then looks back over time to see how conditions/ exposures vary

Question 22

Retrospective study

Answer 22

Relies on data previously collected (as medical records reports). Recall bias (where information was reported incorrectly) can make this type of study inaccurate

Question 23

Recall bias

Answer 23

Where information was recorded and reported incorrectly. Particularly important when considering retrospective studies

Question 24

Prospective study

Answer 24

Has a specific outcomes and recruits suitable participants. Observes exposures and outcomes in these people over time (months/years)

Question 25

Nested case-control study

Answer 25

A case-control study nested inside a cohort study

Question 26

Epidemiology

Answer 26

The study of health related states or events in a specific population and the application of this study to control the health problems

Question 27

Experimental study

Answer 27

This is a study where the conditions are under direct control of the investigator. This usually involves giving a group of people a variable which does not normally arise. A common use of experimental studies is to see how a treatment affects people compared to a group of people not receiving treatment

Question 28

Non-Randomised study

Answer 28

In this type of study, individuals are not randomly assigned to a particular intervention type. Allocation bias and confounding factors may cause distorted results

Question 29

Randomised controlled trial

Answer 29

This is a study where individuals are randomly assigned an intervention type - this could be two treatments, treatment + no treatment or treatment + placebo. This study type is the best way to find whether the treatment is effective

Question 30

Open-Label

Answer 30

This means both investigators and participants know who is getting which treatment - there is no blinding. This can cause bias as patients may change their behaviour or investigators may cause measurement bias. If clinicians are involved, they could introduce non-treatment effect as they change their treatment or attention to the patient

Question 31

Blinding

Answer 31

This is when you do not tell someone whether a person is receiving a treatment or not, and in some cases you don’t even tell them the outcome of their treatment. This person being blinded could be the investigator or patient (single-blind) or it could be both of them (double-blind)

Question 32

As-treated analysis

Answer 32

The analysis of a randomised controlled trial where only those who have completed the trial are included - drop-outs are excluded. Makes the treatment look better than it really is

Pharmaceutical companies often use this analysis when selling their products.

This analysis loses the effect of randomisation.

Question 33

Intention-to-treat analysis

Answer 33

The preferred analysis of a randomised controlled trial as it analyses everybody who is assigned to a treatment group at the beginning of the study - if people drop out, their follow up results are counted as their start results (issued no change following treatment - this prevents making the treatment look more effective than it is).

This analysis gives a more realistic view of what the treatment is like in real-world situations - accounts for likelihood for people continuing the full treatment. Preserves randomisation

Question 34

Clinical equipoise

Answer 34

The reasonable uncertainty or genuine ignorance as to which treatment/intervention is better

Question 35

All studies should follow :

Answer 35

1) Beneficence - Do good
2) Non-maleficence - Non-harming
3) Patient has own choice + makes their own decisions (if suitable)
4) Justice - Be fair