Session 1 Flashcards
What is critical appraisal?
Critical appraisal is the process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context
What is evidence based medicine?
The conscientious, explicit, and judicious use of
current best evidence in making decisions about the
care of individual patients
What is evidence based practice?
Evidence-Based Practice requires that
decisions about health care are based on the best
available, current, valid and relevant evidence.
These decisions should be made by those receiving
care, informed by the tacit and explicit knowledge of
those providing care, within the context of available
resources.
What are the skills required for evidence based practice?
• Translation of uncertainty into an answerable
question. • Search for and retrieval of evidence. • Critical appraisal of evidence for validity and clinical
importance. • Application of appraised evidence to practice. • Evaluation of performance.
How do you develop your question when doing a critical appraisal? Use an example.
– Patient/Population – Intervention/exposure – Comparison – Outcome
We are interested in exploring any relationship between parental smoking and risk of asthma in children.
Slide 7 lec 1
Initial key questions to answer when looking at a paper when doing a critical appraisal
- Is this article relevant to my interests?
- Is there a clear research question?
- When was it published?
- Has it been peer reviewed?
- Do I want to proceed?
Why do articles get rejected?
• The study did not address an important scientific issue • The study was not original (someone else had already done the same or a similar study) • The study did not actually test the authors’ hypothesis • A different type of study should have been done • Practical difficulties (in recruiting subjects, for example) led the authors to compromise on
the original study protocol • The sample size was too small • The study was uncontrolled or inadequately controlled • The statistical analysis was incorrect or inappropriate • The authors drew unjustified conclusions from their data • There is a significant conflict of interest (one of the authors, or a sponsor, might benefit
financially from the publication of the paper and insufficient safeguards were seen to be
in place to guard against bias) • The paper is so badly written that it is incomprehensible
Summarise the process of a critical appraisal
• Formulate the PICO Question • Identify Keywords for each PICO Element • Plan the Search Strategy • Execute the Search • Refine the Results • Review the Literature • Assess the Evidence
What are the key issues across all study designs when doing a critical appraisal?
• The research question and aim:
– Often found at the end of the background/introduction
section – You should be able to apply PICO to what is
presented – Can you easily identify the primary outcome of
interest? – Do you think that this study could be generalizable or
applicable to your patient or population of interest?
How can bias present in a critical appraisal?
- Selection bias – is there a systematic difference between
the people that have been selected and those that have
not? - Is how the study sample was developed described? - Are the characteristics of the sample well described? - Is there any evidence that the sample is generalizable to the
wider population? - Data collection – how were data collected and how might
that impact on the study findings? - Is the data self-reported? - Does it rely on recall? - Were validated tools used? - What was the response rate and what do we know about non-
responders? - How many people dropped out and what do we know about
them?
How to check for confounding factors in a critical appraisal?
• What are the potential confounding factors for
this study? • Are potential confounding factors discussed? • Are potential confounding factors adjusted for?
How to makes sense of the results when doing a critical appraisal?
• What is the sample – how is the study sample
described? • Is any justification given regarding the size of the
sample? • What statistics are presented – what is the
outcome measure presented? • How are figures and tables presented? • Are the results statistically significant? • Are the results generalizable?
How should findings be discussed in study when doing a critical appraisal?
• Is the main finding of the study clearly given and
does it reflect the aim of the study? • How does this study fit with what we already
know? • Are strengths and limitations discussed? Has
anything been missed? • Is a clear final conclusion given as well as
recommendations for practice/next steps?
Benefits and disadvantages of a cross sectional study?
• Are useful for determining burden of disease in a
population – i.e. prevalence • Good for generating hypotheses • They can be descriptive or they can be analytical • They can be relatively easy and quick to do – no
long follow up period for example • They are a ‘snapshot’ so can’t determine temporal
sequence • They are prone to bias and confoundin
What are we most concerned about when appraising a cross-sectional study?
• Selection bias and how representative the
sample is of the population • Response bias • Measurement bias • Confounding
