collecting the evidence

Question 1

how to practise EBM?

Answer 1

• craft a clinical question
• search the medical literature
• find he study that will best answer the questions
• perform a critical appraisal
• determine how the results will help you care for your patient
• evaluate the results in your patient population

Question 2

3 principles of a good question?

Answer 2

1) define precisely whom the question is about

2) define the option you are considering and possible comparison

3) define the desired outcome

Question 3

what should the question involve ?

Answer 3

Patient
intervention
comparison
outcome
PICO

Question 4

systematic review/meta analysis?

Answer 4

secondary sources on information vetted by independent researchers and clinicians

Question 5

what are the clinical practise guidelines?

Answer 5

reviews covering large disease groups and treatment strategies
(NICE guidelines)

Question 6

how do you construct a hypothesis?

null hypothesis?
alternative hypothesis?

Answer 6

is one set of data different from another?

null hypothesis= two sets of data are from the same population and not different.

alternative hypothesis= two sets of data are from different populations and are different.

Question 7

when trying to answer a clinical question, what questions should you try to answer?

Answer 7

1) start with:
- Cochrane reviews
- NICE and SIGN guidelines

2) then use:
- MedLine

Question 8

different ways you can interoperate the evidence?

Answer 8

• how are the clinical studies designed
• are there different types of data
• hypothesis testing
• confides intervals
• odds ratio
• forrest plots

Question 9

what are the 2 types of quantitative evidence?

Answer 9

discrete = can only have certain numerical values (number of children)

continuous = do not have discrete steps (heigh and weight)

Question 10

data types:

what are the 2 types of categorical variables?

Answer 10

nominal (unordered category)
- male/female, green/blue eyes, alive or dead.

ordinal (ordered category)
- objective = heavy, moderate or light drinks, grade of bread cancer

subjective = health status questionnaires

Question 11

how do you test a hypothesis?

Answer 11

• assume the null hypothesis
• determine the probability that the null hypothesis is correct (P value)

Question 12

what is the P value?

Answer 12

a P value of 0.1 means that there is a 0.1 probability or//

• 10% chance
• 1 in 10 chance
  that the null hypothesis is correct

(this Is the same as saying that there is a 1 in 1o chance there is no different between the data sets)

Question 13

what happens if the P value is <0.05?

Answer 13

an arbitrary cut off of 0.05 or 5% (1 in 20 chance) is used to indicate that the null hypothesis can be reasonably rejected

if P< 0.05 then there is a statistically significant difference.

Question 14

what is the Power of a test?

Answer 14

the power of a test is its ability to reject the null hypothesis when it is false
- the capacity to detect an effect if one is present

Question 15

what is a type I error?

Answer 15

rejecting the null hypothesis when it is true (false positive) - concluding there is an effect when there isn’t (P is small)

Question 16

what Is a type II error?

Answer 16

not rejecting the null hypothesis when it is false- concluding there is no effect when there is (P will be large)
false positive

Question 17

P>0.1?

P>0.05

Answer 17

> 0.1 = no evidence against the null hypothesis. the data appears to be consistent with the null hypothesis.

> 0.05 = weak evidnce against the null hypothesis in favour of the alternative.

Question 18

considering that the level of analyse correlates with health or sickness, what will a low and a high analyse correlate to?

Answer 18