Critical Appraisal

Question 1

To weigh up the evidence critically to assess its validity (closeness to the truth) and usefulness (clinical applicability) “[Sackett and Haynes, 1995

Answer 1

Critical Appraisal

Question 2

are the results valid?
Is the research question focused?
Was the method appropriate?
How was it conducted, e.g. randomisation, blinding, recruitment and follow up?

Answer 2

Rigour

Question 3

: what did the research find?

Answer 3

REsult

Question 4

Will the results help my work with patients?

Answer 4

Relevance

Question 5

validity relates to the quality of the study design in terms of the methods of a study: where bias is reduced as far as possible, where instruments are reliable and safeguards have been put in place to ensure trustworthiness.

Answer 5

Internal validity

Question 6

is the degree to which the results of a clinical study can be applied to clinical practice in a specific setting.

Answer 6

External validity

Question 7

relates to the trustworthiness of the results.

Answer 7

REliability

Question 8

relates to whether a particular treatment or form of care that demonstrated an overall effect in a study can be expected to provide the same effect for an individual or group in a specific clinical or population setting

Answer 8

Applicability

Question 9

the ability to reliably apply the results of a study to other populations, based on the characteristics of the subjects, size of the sample, the setting and trustworthiness of the study.

Answer 9

Generalisability

Question 10

is the absence of any cause of events that can be predicted understood or controlled. It is the unknown and unpredictable element in happenings that seem to have no assignable cause.

Answer 10

Chance

Question 11

is where the sample size used in a study is partly determined on the need to have sufficient statistical power (strength) to make inferences about a population from the sample.

Answer 11

Power

Question 12

is the deviation of a measurement from the ‘true’ value leading to either an over or under-estimation of the treatment effect. Bias may originate from different sources: allocation of patients, measurement, interpretation, publication and review of data.

Answer 12

Bias

Question 13

is a method of analysis for randomised controlled trials in which all patients randomly assigned to one of the treatments are analysed together, regardless of whether or not they completed or received that treatment, in order to preserve randomisation

Answer 13

Intention-to-Treat analysis

Question 14

is the ratio of the rates of outcome in the treatment and control groups. This expresses the risk of the outcome in the treatment group relative to that in the control group.

Answer 14

RR or Relative Risk

Question 15

is the interval within which the population parameter (the ‘true’ value) is expected to lie with a given degree of certainty (eg 95%).

Answer 15

CI or Confidence Interval

Question 16

is the probability that a particular result would have happened by chance.

Answer 16

p value

Question 17

Uses numbers to describe and analyse
Useful for finding precise answers to defined questions
Objective process
Deductive reasoning
Statistical sampling

Answer 17

Quantitative

Question 18

Uses words to describe and analyse
Useful for finding detailed information 
about people’s attitudes / perceptions
Subjective process
Inductive reasoning
Theoretical sampling

Answer 18

Qualitative

Question 19

Measures effectiveness of intervention over time

Answer 19

Cohort study

Question 20

Comparative: what makes some populations different from others

Answer 20

Case-controlled study

Question 21

Whether one intervention is better than another

Answer 21

Clinical trial

Question 22

measures overall effect of several clinical trials

Answer 22

Systematic review / meta-analysis

Question 23

Preventing those involved in a trial from knowing to which comparison group,

i.e. experimental or control, a particular participant belongs

Answer 23

Blinding

Question 24

Participants, caregivers, outcome assessors and analysts can all be blinded

Answer 24

BLinfing

Question 25

Analysing people, at the end of the trial, in the groups to which they were randomised, even if they did not receive the intended intervention
Prevents attrition bias: caused by patients withdrawing from a trial
Paper should specify if ITT was or was not used

Answer 25

Intention-to-treat analyses

Question 26

is the probability of an event occurring compared to the probability of it not occurring

Answer 26

Odds

Question 27

Represents the probability that the result could have occurred by chance if the null hypothesis was true

Answer 27

P-value

Question 28

Assesses significance of a given sample

Answer 28

Confidence interval