Preventing Childhood Obesity - Evidence Policy and Practice.pdf

Chapter 19
innovation in intervention development. All too
often, the research proposals submitted and funded
are strong in terms of trial methodology, but very
weak in terms of the proposed intervention, drawn up
by a group of “ experts ” with no public involvement,
and a weak and unidisciplinary theoretical and empirical
basis. There is an inevitable bias towards relatively
simple, individually targeted interventions rather than
more complex, multi - level interventions and programs.
On the other hand, complex multi - level or
settings - based interventions developed in conjunction
with the target audience and based on strong theory,
are typically evaluated using weak research designs
with either no estimate of effect due to the absence of
a summative evaluation, or potentially biased effect
estimates at best.
How to r eorient t owards h elpful, r igorous
e valuation d esigns
A helpful way to move away from this stereotype and
to prevent the perpetuation of an inadequate evidence
base is to recognize the different stages of research
needed in the development, evaluation and implementation
of complex interventions. In health
promotion, there are a number of models of stages
of intervention research and evaluation, including
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Nutbeam ’s six-stage development model. and
Green ’s Precede/Proceed framework, 16 which identify
different research questions and the various
research methods that are appropriate at each stage.
The United Kingdom Medical Research Council
(MRC) also published a framework for the evaluation
of complex interventions 17 which identified five
research stages, mirroring the stages of drug development
research, of which the fourth stage was the
definitive randomized controlled trial. This model has
been particularly helpful in highlighting the need for
interventions to have been thoroughly developed
through the prior stages, which may involve theoretical
development, qualitative testing, modeling, feasibility
testing and an exploratory trial, prior to
large - scale summative evaluation, thus limiting the
reproduction of the stereotype described in the previous
paragraph. Box 19.2 gives an example of an intervention
that has passed through a member of research
stages prior to the final trial phase.
Notwithstanding necessary simplification, we provide
recommendations for selected research designs
Box 19.2 Case s tudy: fun ’ n
h ealthy in Moreland!
A series of obesity prevention studies conducted in
Victoria, Australia demonstrate how the different
research stages can be developed. A review of the
child obesity literature was conducted in 2004 and
highlighted the increasing prevalence of child overweight
and obesity and the complexity of environmental
and socio - cultural determinants. A clear gap in the
evidence base in relation to effective interventions led
to the development of a pilot study conducted in three
diverse primary schools — in inner urban, suburban
and rural areas. This formative evaluation was conducted
to test the feasibility and acceptability of a trial
methodology, and a range of school, parent and child
measures. As a result of this pilot study, the methodology
and measures were adjusted to improve acceptability
and comprehensibility and a study design was
developed using a socio - environmental theoretical
framework actioned by the Health Promoting in
Schools Framework and culturally competent community
development strategies. A five - year cluster
randomized controlled trial, fun ’ n healthy in Moreland!,
was consequently implemented in 2004. This child
health promotion and obesity prevention intervention
and research study involves 24 primary schools in an
inner - urban, culturally diverse area of Melbourne,
Australia. It is being conducted in partnership with the
local community health service. A comprehensive
mixed method summative evaluation will allow an
assessment of what worked, for whom, how, why and
at what cost. 27
for each of the two main stages of evaluation research,
formative and summative. These stages can be mapped
onto the three frameworks referenced above, and
provide a useful classification to aid the presentation
of key issues in evaluation research design. However,
it is not intended to suggest that the identification of
specific research questions can only be done with reference
to this sequence. Indeed, as we describe below, it
is likely that key questions regarding the acceptability,
implementation and causal mechanisms of an intervention
will need to be addressed at each of these stages.
Formative e valuation
By identifying five research stages that are comparable
to the stages of drug development research, the MRC
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