Critical appraisal of the evidence

Word limit: Not more than 3 pages (not counting the title page, reference list or attachments)
Background information:
The main aim of the first assessment item is to familiarise you with an evidence-based approach to nutrition research. You will collect and critically evaluate the evidence relating to your research project; examples of how to do this will be provided in tutorials. Specific instructions follow:
1.Write your topic and research project, together with your name, on a title page, which forms page 1.

2. Search for sources of evidence on nutrition interventions in your chosen topic area. Depending on the nature of your project, you may be looking for evidence of a problem existing, or for interventions to prevent or treat the problem. This could be in the form of systematic reviews, articles about interventions or official reports. See Figure 1 and instructions below to see how much searching you need to do:

FIGURE1: HIERACHY OF EVIDENCE
Level III-3
Comparative study without controls
Historical control study
Two or more single arm study
Interrupted time series with no control
Level I
Systematic review of Randomised Control studies ( i.e. Level II studies)
Level III-2
Non-randomised control trial
Cohort study
Case-control
Time series with a control
Level III-I
Well designed pseudo-RCT s (alternate allocation or some other method)
Level IV
Case series with either pre or post test outcomes
Cross-sectional study
Level II:
Well conducted
Randomised Controlled Trials ( RCT s)

Process:
You need to find 3 sources of evidence (i.e. journal articles). You should look for the HIGHEST level of evidence, and work your way down the levels of evidence (i.e. the diagram above) until you have 5 sources of evidence.
This means, you start by looking for a systematic review.
– If there are 3 systematic reviews you do not have to look any further.
– If there are <3 systematic reviews you need to look for randomised control trials and so on This process should be continued until you have 3 sources of evidence. Tips for searching and journal article selection - The Cochrane database should be your first point of call for systematic reviews. Please check however that they are completed systematic reviews and not just a protocol (i.e. a systematic review in progress). - Select the most recently conducted systematic reviews/studies (i.e. within 3-4 years). Otherwise you should move down the levels of evidence. - Don t be surprised if you have to use Level III evidence, not all topics will have up-to-date systematic reviews. 3. Evaluate the level of each source of evidence using the following NHMRC levels: I “ Evidence obtained from a systematic review of all relevant Randomised control trials (RCT s) II “ Evidence obtained from at least one properly designed RCT III-1 “ Evidence obtained from well-designed pseudo RCT s III-2 “ Evidence obtained from comparative studies (including systematic reviews of such studies) with concurrent controls and allocation not randomised, cohort studies, case-control studies III-3 Evidence obtained from comparative studies without a control (interrupted time series without a parallel control group) IV “ Evidence obtained from case series, either post-test, or pre/post 4. Document each relevant piece of evidence you have collected by summarising them in an evidence table. A sample table will be placed on Moodle, but should be NO MORE THAN 2 pages. The aim of the evidence table is for the reader to extract the main details of the source document, without having to actually read the source document. It should be laid out in such a way as to facilitate comparison between articles. You can use scientific abbreviations and use a small font (eg Arial narrow, 9 point) to keep the table within limits. This will form pages 3-4. 5. Write a 1 page summary of your findings on the strength/quality of the evidence for an intervention that were described in the Table (NB. Focus on the evidence quality rather than describing details of the intervention (these were in your table). This will form page 2. 6. Attach a reference list of all the articles that appear in your evidence table and summary. Use the Vancouver referencing system. Place this page last ie page 5.

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