evidence Flashcards Preview

BDS2 PHMP > evidence > Flashcards

Flashcards in evidence Deck (24)
Loading flashcards...
1
Q

what is the formula for risk?

A

no. events of interest/total no. observations

2
Q

what is the formula for odds?

A

no. events of interest/ no. w/o event

3
Q

what is starting risk?

A

chance of outcome in untreated group

4
Q

what is modified risk?

A

chance of outcome in treated group

5
Q

what is relative risk reduction?

A

overestimates benefit as small reductions sound big

6
Q

what is the value of no difference?

A

when the absolute risk difference = 0

7
Q

when does the absolute risk dif = 0?

A

if no dif in values (treated vs untreated)

8
Q

what is number needed to treat? (NNT)

A

no. px needed to treat to prevent one px from developing disease

9
Q

what is the formula for NNT?

A

1/ARD

10
Q

what is the formula for risk ratio? (RR)

A

risk in tx group/ risk in placebo group

11
Q

what is RR if risk groups are equal?

A

1, value of no dif

12
Q

what is an odds ratio?

A

ratio of odds of outcome in both groups

13
Q

what is OR if odds in groups equal?

A

1, value of no dif

14
Q

what is a confidence interval?

A

range of values a true population tx effect is likely to lie

15
Q

how would you get value of no dif from CI?

A

insufficient evidence

16
Q

what is understood if CI doesn’t contain value of no dif?

A

sufficient evidence

17
Q

what is the value of no dif for ratio?

A

1

18
Q

what is the value of no dif for difference?

A

0

19
Q

what is an observational uncontrolled study?

A

researchers watch

20
Q

what is a controlled cohort/case study?

A

observe what happens in dif situations

21
Q

what are randomised controlled trials?

A

intervention/placebo

gives strongest evidence

22
Q

what is a case report/series?

A

report on px w/ outcome of interest

no control

23
Q

what is a cross sectional study?

A

study of people w/ disease + control group w/o

24
Q

what is a cohort study?

A

establish group, measure exposures, follow up, identify those that develop disease