TL: Critical Appraisal

Question 1

Critical Appraisal

Answer 1

The process of assessing and interpreting evidence systematically, considering its validity, results, and relevance.

Question 2

Hypothesis

Answer 2

An educated guess on the nature of the patient’s illness, usually obtained by selecting those diseases having the same history or physical examination characteristics as the patient

Question 3

Peer-Reviewed literature

Answer 3

f

Question 4

Textbook

Answer 4

f

*systematic review, typically not critically appraised?

Question 5

Systematic Review

Answer 5

A formal review of a focused clinical question based on a comprehensive search strategy and structured critical appraisal of all relevant studies.

Question 6

Expert opinon

Answer 6

Opinions, not critically-appraised by a structured scientific method, voiced or communicated by an individual. The level of clinical expertise of the individual certainly holds merit so the level of strength of opinion does as well.

Question 7

Hierarchy of Evidence

Answer 7

A system that grades evidence or published information related to healthcare, according to the strength of scientific merit that produced the evidence. The model used by ArizonaMed EBDM places Level 1 evidence at the top. Level 1 evidence is typically the result of Systematic Reviews or very large RCTs. Level 2 evidence is typically the result of Prospective Observational Studies, e.g., prospective cohort study. Level 3 evidence is typically the result of Retrospective Observational Studies, e.g., case-control study. Level 4 evidence is typically the result of a Case Series. Level 5 evidence is typically found in Textbooks or Expert Opinion that have not been critically-appraised.

Question 8

Internal Validity

Answer 8

The study design performance at measuring differences, if they exist, between groups
eg, intervention and control, that are due only to the hypothesized effect.
*the quality of the scientific method used, typically the study design chosen; is it appropriate?

Question 9

Construct Validity

Answer 9

A construct is a theoretically derived notion of the domain(s) we wish to measure. An understanding of the construct will lead to expectations about how an instrument should behave if it is valid. Construct validity therefore involves comparisons between measures, and examination of the logical relationships, which should exist between a measure and characteristics of patients and patient groups. Essentially, does the study aptly measure what it proposes to measure? In social science and psychometrics, construct validity refers to whether a scale measures the unobservable social construct (such as “fluid intelligence”) that it purports to measure. It is determined after studies show correlation between the measure itself and the characteristics it is aimed at.

*does the study measure what it proposes to measure; ex: are the outcomes chosen true representations of the disease outcomes you care about in your patient(s)?

Question 10

External Validity

Answer 10

The same as “Applicability” (The degree to which the results of a study are likely to hold true in your practice setting. Also called external validity, generalizability, particularizability, relevance.) Are the patients in the study similar to the patients you might apply the evidence to?

Question 11

Statistical Significance

Answer 11

A measure of how confidently an observed difference between two or more groups can be attributed to the study interventions rather than chance alone.When statistically significant, the probability of the observed results, given the null hypothesis, falls below a specified level of probability (most often P < 0.05).Describes the probability of incorrectly rejecting the null hypothesis and concluding that there is a difference when in fact none exists (i.e., probability of Type I error). Many times this probability is 0.01, 0.05, or 0.10. For medical studies it is most commonly set at 0.05.

Question 12

Clinical Significance

Answer 12

Results that make enough difference to you and your patient to justify changing your way of doing things. For example, a drug which is found in a mega trial of 50000 adults with acute asthma to increase FEV1 by only 0.5% (P < 0.0001) would fail this test of significance. The findings must have practical importance as well as statistical importance. (See statistical Significance.)

Question 13

What are examples of descriptive study designs?

Answer 13

• case report
• case series
• cross-sectional study

Question 14

What are examples of observational - retrospective study designs?

Answer 14

• case-control
• retrospective cohort
• outcome and effectiveness registries

Question 15

What are examples of observational - prospective study designs?

Answer 15

• cohort

Question 16

Analysis

Answer 16

the statistical methods, results, and conclusions of the study
are they appropriately conducted and stated?

Question 17

Application

Answer 17

the relative impact or importance of the study to your practice of medicine
ex: how would I apply this knowledge to my patient(s) and how important is it?

Question 18

The quality of evidence is what you are trying to measure via the process of what?

Answer 18

critical appraisal