TABLE 4.

Summary of studies focussing on referral filtering schemes, grouped based on outcomes assessed.

Focus	Author(s)	Year	Location
Cost assessment	Forbes et al. 25	2019	UK
	Mason et al. 28	2017	UK
Acceptability	Barrett and Loughman 29	2018	Ireland
	Baker et al. 30	2016	UK
	Konstantakopoulou et al. 31	2014	UK
Clinical impact	Kanabar et al. 32	2021	UK
	Huang et al. 33	2020	Australia
	Phu et al. 34	2020	Australia
	Gunn et al. 35	2019	UK
	Bowes et al. 36	2018	UK
	Konstantakopoulou et al. 37	2018	UK
	Ly et al. 38	2017	Australia
	Ly et al. 39	2016	Australia
	McAlinden et al. 40	2016	UK
	El‐Assal et al. 41	2015	UK
	Roberts et al. 42	2015	UK
	Keenan et al. 43	2015	UK
	Ratnarajan et al. 44	2015	UK
	Ratnarajan et al. 45	2013a	UK
	Bourne et al. 46	2010	UK
	Park et al. 47	2009	UK
	Ang et al. 48	2009	UK
	Lash et al. 49	2006	UK
Mixed focus	Wang et al. 50	2021	Australia
	Ford et al. 51	2019	Australia
	Konstantakopoulou et al. 52	2016	UK
	Ratnarajan et al. 53	2013b	UK
	Devarajan et al. 54	2011	UK
	Parkins and Edgar 55	2011	UK
	Syam et al. 56	2010	UK
	Sheen et al. 57	2009	UK
	Henson et al. 58	2003	UK