Measuirng health 2 Flashcards
wk 5
What does relative risk indicate?
likelihood of developing in exposed vs not exposed?
How is relative risk calculated?
ratio of: incidence in exposed / incidence in non-exposed
What is relative risk most commonly used in?
cohort studies
What does an RR > 1 mean
risk of disease (may have) INCREASED after exposure
what does an RR<1 mean
risk of disease (may have) decreased after exposure
What is the odds ratio commonly used in and why?
case-control studies. We start with the disease so there is no CI therefore can’t calculate RR
What is absolute risk the same as?
Cumulative incidence
how is cumulative incidence calculated?
no of new cases/ no of people at risk in population
What is Risk difference?
the difference in incidence between exposed and not exposed.
How is risk difference calculated?
CI of exposed - CI of not
What is the calculation for the Odds ratio?
odds that case was exposed / odds that control was exposed
What does an OR> 1 indicate?
exposure may increase risk of disease
What does NNT stand for? and calculation
The number needed to treat. = 1/Absolute Risk Reduction
What is p-value?
probaility that the result observed in the sample date is due to chance, given that null hypothesis is true
What is p-value the result of?
statistical hypothesis test
what is a statictal hypothesis test?
the method that quantifies the probability of obtaining a difference as large as the one observed.
null hypothesis
no true difference between groups
what is the hypothesis called when there is a difference?
study/ alternative hypothesis
What happens if the p-value < 0.05
LOW probability of being a chance finding = reject null and accept that they are statistically different.
Where is the true value often reported to be?
at 95% confidence level
What is a confidence interval?
Range in which reflects a certain degree of assurance of where the true value lies.
Should p value be reported alone to show statistical significance?
no- also consider confidence level, and risk/odds ratio
What are the studies that use qualitative research methods?
interviews, fieldwork and focus groups
What are the advantages of qualitative studies?
They are subjective and personal, consider human behaviours and factors, are exploratory and examine patterns and themes
In a two-way table for RR- what goes on top and what is on the side?
Top= Outcome (D+ and D-)
Side= exposure (E+ and E-)
do you need to mention follow-up in the analytical study?
yes
What is relative risk AKA?
risk ratio
Can the 95% confidence interval tell you if an odds ratio or a relative risk is statistically significant without knowing the p-value? Explain.
What is the differnce between AR and RR?
AR= actual probability event will occur whilst RR is a risk of an event occurring in the study group versus the control group
How is relative risk calculated?
1 - RR. Expressed as % of age
How much Absolute risk always be expressed?
in regards to unit of time
