Critical Appraisal

Question 1

What is the framework for question searching?

Answer 1

PICO:
Population
Intervention
Control
Outcome

Question 2

What is the best study design for diagnosis?

Answer 2

Cross-sectional study, which takes data from a singular point in time such as a survey and analysing the results.

Question 3

What is the best study design for aetiology?

Answer 3

Case control study that is population based
Cohort study

Question 4

What is the best study design for quality evaluation?

Answer 4

Descriptive studies like surveys or qualitative research

Question 5

What is the best study design for prognosis?

Answer 5

Cohort studies

Question 6

What is the best study design for treatments?

Answer 6

RCTs or Systematic Review of RCTs

Question 7

How is a systematic review beneficial?

Answer 7

Results from all available evidence from unpublished research and those not in the English Language
Sensitivity analyses can be performed
Sub-group analyses can be carried out
Can indicate heterogeneity between studies
Increases the total sample size that will increase certainty and precision

Question 8

What is bias?

Answer 8

Systematic introduction of error in a study that distorts the results.

Question 9

What are important calculations for research designs towards treatments?

Answer 9

Treatment research designs are RCTs.
Relative risk, absolute risk, odds ratio, confidence interval and number needed to treat.

Question 10

What are important calculations for research designs towards diagnosis?

Answer 10

Research study designs are cross sectional studies.
Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio.

Question 11

What are important calculations for research designs towards prognosis?

Answer 11

Prognosis research study design is cohort studies or case-control.
Relative risk or odds ratio.

Question 12

What are important calculations for research designs towards aetiology?

Answer 12

Research study designs are
Relative risk reduction, odds ratio and and number needed to harm.

Question 13

What are important considerations for using the results of a research study for decision making?

Answer 13

Generalisability of the results to the patient population that you are treating
Availability of the desired outcome from the study that is provided by the local health service.

Question 14

How should you critically appraise a study?

Answer 14

->Clearly focused question based on population, intervention given and outcomes considered
->Research design chosen is appropriate
-> How they attempted to identify all relevant studies, including the database used and unpublished non-English studies
->How the quality of te study was assessed based on a scoring system or pre-determined strategy
->If a confidence interval or p value was reported
->How the results are presented e.g odds ratio and the significance/size of the result
-> Generalisability
-> Consideration of outcomes from different perspectives
-> Benefit from change

Question 15

How should studies which have combined the results of multiple trials be appraised?

Answer 15

Whether there were tests for heterogeneity
Variations in the results were discussed
Results of each study are displayed

-> Ideally, combined results should use similar outcomes

Question 16

What do valid studies include as part of evidence?

Answer 16

They include studies even with null or negative results that are more likely to be unpublished

Question 17

What is hand-searching?

Answer 17

Manual process to identify relevant studies to include in a systematic review which includes:
->Checking reference lists of documents
->Looking at pages of journals or conferences

Question 18

Why is hand-searching important?

Answer 18

This is because:
Important for not overlooking relevant articles
Searches may not include enough relevant key terms
Sources are not included in traditional databases

Question 19

How can systematic review ensure quality?

Answer 19

Researchers assess the studies for validity using pre-determined criteria

Question 20

What is weighted mean difference?

Answer 20

Each individual study in a meta-analysis/systematic review will have a mean difference based on their results. Because each study will have varying levels of validity, the weight it has on the meta-analysis will differ. The weighted mean difference is:

Mean difference x weight of the study

Question 21

What is standardised mean difference?

Answer 21

Used in a meta-analysis when the studies being compared are answering the Same question but have different units. Therefore, the standard deviation is used.

Question 22

What is the calculation for standardised mean difference?

Answer 22

Mean difference/ standard deviation

Question 23

How can the quality of information be assessed?

Answer 23

Cochrane library uses GRADE