Further research needed

The evidence base for this intervention is made up of largely poor quality studies.

Explanation: 
Majority of studies are appraised as being of poor quality, but are still showing an effect in favour of the intervention.  

Further considerations: 
More robust primary research and thorough evaluation needed. 

OR 
Majority of studies are appraised as being of poor quality and of no effect. 

The evidence base is inconsistent. There may be some evidence supporting the use of this intervention, but it is not conclusive.

Explanation: 
The results of studies are inconsistent with no clear majority in favour or not in favour of the intervention, regardless of quality.

Further considerations: 
More robust primary research and thorough evaluation needed.

There is a lack of evidence for this intervention 

Explanation:  
Only one study has been identified for this intervention (regardless of quality.)

Further considerations: 
More primary research and thorough evaluation needed.