Idiopathic toe walking and sensory processing dysfunction

Table 3 Designations of levels of evidence as proposed by NHMRC.

Level	Aetiology
I	A systematic review of level II studies
II	A prospective cohort study
III-1	All or none^§§§
III-2	A retrospective cohort study
III-3	A case-control study
IV	A cross-sectional study/case series

§§§ All or none of the people with the risk factor(s) experience the outcome. For example, no smallpox develops in the absence of the specific virus; and clear proof of the causal link has come from the disappearance of small pox after large-scale vaccination.
Modified from "Designations of levels of evidence* according to type of research question (including tablenotes)" [72, 73]

ISSN: 1757-1146