Table 2. National Health and Medical Research Council Hierarchy of Evidence [27].

Level	Definition
I	A systematic review of level II studies.
II	A randomised controlled trial.
III-1	A pseudorandomised controlled trial (alternate allocation or some other method).
III-2	A comparative study with concurrent controls (non-randomised experimental trial, cohort study, case-control study or interrupted time series with a control group).
III-3	A comparative study without concurrent controls (historical control study, two or more single arm study or interrupted time series without a parallel control group).
IV	Case series with either post-test or pre-test/post-test outcomes.