Implementing the guideline

What is a recommendation?

Some recommendations can be made with more certainty than others. The wording used in the recommendations in this guideline denotes the certainty with which the recommendation is made (the 'strength' of the recommendation).

The 'strength' of a recommendation takes into account the quality (level) of the evidence. Although higher-quality evidence is more likely to be associated with strong recommendations than lower-quality evidence, a particular level of quality does not automatically lead to a particular strength of recommendation.

Other factors that are taken into account when forming recommendations include: relevance to the NHS in Scotland; applicability of published evidence to the target population; consistency of the body of evidence, and the balance of benefits and harms of the options.

What is a good practice point?

Levels of evidence key

1++

High-quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias

For a high-quality systematic review of studies with a high risk of bias, the risk of bias will be stated in the text

1+

Well-conducted meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias

1-

Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of bias

2++

High-quality systematic reviews of case-control or cohort studies

High-quality case-control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal

2+

Well-conducted case-control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal

2-

Case-control or cohort studies with a high risk of confounding or bias and a significant risk that the relationship is not causal

3

Non-analytic studies, e.g. case reports, case series

4

Expert opinion