L3 07/02 Flashcards
In order to have base changes in practice on evidence we need to have what 2 things?
- A good range of available evidence
- High quality of available evidence
How do we find the evidence we need to decide whether we change our practice or not?
- Conduct literature searching as you would conduct research > Research questions THEN methods THEN results > Analysis of results THEN conclusion
- Ask the right question > What are you looking for exactly?
Once we have found the question, where do we ask it?
- Scope the databases so that you can adopt a logical and systematic plan for your search
- Adopt a flexible approach
What are our key sources of information?
- Journal data bases are searchable electronic storage of journal articles, conference proceedings and papers, reports, government and legal publications, patents, books
- A search will give you the citations
What is the difference between a database and a search engine?
- The search engine allows you to search the databases, but it is NOT a database and is only as good as the instructions you provide it
- It doesn’t have the information you need but allows you to find it
Why is google scholar frowned upon?
- Information not usually peer reviewed for accuracy
- Listing order is determined according to financial input
Lack of appropriate evidence can be due to one of two things…
- A small evidence base
- Issues with the search strategy
Name 3 common search problems
- Poor question
- Spelling mistakes
- Wrong key words
What is critical appraisal?
A systematic assessment of the quality of research evidence to determine whether it can inform practice.
What are the 3 aspects of appraisal?
- Trustworthiness
- Value
- Relevance
What are 4 key questions - trustworthiness?
- Is there any potential bias?
- Is the method reliable?
- Is the study valid?
- Do we accept the results?
What are 4 key questions - value?
- Are the results clinically important?
- What is the strength of the effect?
- How confident can we be in the results? (statistical significance)
- Can we actually use the results?
What are 4 key questions - relevance?
- Can the results be applied to the question?
- Is the cohort the same?
- Are these results actually useful to us?
- Has the research been conducted on the same kinds of people and conditions as what we want to apply it to? (external validity - generalisability)
What is reliability and what does it involve?
- If you do something repeatably you achieve the same answer/outcome
- It is about consistency across time (test-retest reliability), across items (internal consistency), across researchers (inter-rater reliability)
What is validity and what does it involve?
- Relates to how accurate the answer/outcome is
- The extent to which the scores from a measure represent the variable they are intended to
- Different types: face, external, internal, ecological
Critical appraisal demands the following skill set (6)
- High level thinking skills
- Knowledge of the subject area
- Understanding of health research methods and statistics
- Knowledge of the wider context
- The ability to identify relationships between ideas and concepts
- Developing judgements about study trustworthiness, value and relevance
What are the 4 appraisal tools?
- Jaded scale (Oxford quality scoring system)
- McMaster critical review guidelines
- CASP tools
- SIGN checklists
What does the the Jaded scale (Oxford quality scoring system) entail?
- A simplistic method of evaluating clinical trials
- Designed to assess the methodological quality of clinical trials
- Simple scoring method based on key threats to validity in the design of a clinical trial (randomisation, blinding, attrition)
- Limitations: Over simplistic, too much emphasis on blinding, not applicable to to other research designs
What does the the McMaster critical review guidelines entail?
- Detailed guidelines provided for different research designs in healthcare studies. No overt scoring method, but rather a set of questions to facilitate overall judgement of research quality
- General set of questions/prompts to get you thinking about the research question
What does the the CASP tools entail?
- 3 sections: Are the results valid? Are the results clinically important? Will the results help locally?
- 8 checklists covering different types of evidence: Trials, Reviews, Cohort studies, Case control studies, Qualitative studied, Economic evaluations, Diagnostic test studies, Clinical prediction rule
What are SIGN checklists?
A series of checklists for different types of evidence:
Systematic reviews and meta-analysis, Randomised controlled trials, Cohort studies, Case-control studies, Diagnostic studies, Economic studies, Considered judgement pro-forma
What is the hierarchy of evidence?
A way of ranking how useful different pieces of evidence are particularly in relation to evidence-based practice
Suggest 4 appropriate search terms to locate evidence answering the following research question: What effect does an increased dose have on intellectual development in children undergoing radiotherapy?
- Dose
- Paediatric
- Radiotherapy
- Intellectual
Suggest some real health or medical databases?
- Medline
Can any keyword can be used as a MeSH term?
No, there is a pre-determined list of MeSH terms so not any old keyword will be in there
Is critical appraisal the process of assessing the quality of a piece of evidence?
Yes
Is critical appraisal best summarised as finding the faults with articles in the evidence base?
No, as it can also include positive elements of the article
Are reliable studies those that are likely to yield the same results if repeated?
Yes
Are valid studies those that are clinically important and relevant to the research question?
No
Give 3 recognised critical appraisal tools
- CASP
- Jaded scale
- SIGN
Hierarchy of evidence (increasing)
- Animal studies
- Editorials
- Case reports
- Cohort studies
- Randomised controlled trials
- Systematic reviews
