Existing SNHV trials show relatively
modest effects (effect sizes of 0.2 — 0.4 SDs) for
outcomes such as child mental health and behaviour, and cognitive and language development, from infancy to mid - childhood.19 While effect sizes of 0.25 — 0.3 SDs can be meaningful and impactful
at the whole of population level, 59 targeted public health interventions such as SNHV include a
cost and intensity such that larger effects in the short - to - medium term might be necessary to justify implementation
at a population level.
Although treatment effects for several
outcomes were small in magnitude, as reported previously, HS was
modest in intensity and
cost, relative to other early intervention efforts.5 For example, HS families made 11 well - child visits and received < 2 home visits within their child's first 2.5 years,
at a
cost of $ 402 to $ 933 / year.