Introduction
The 2000 MRC framework (1)suggests a
linear progression through the stages of the development and
evaluation of a complex intervention, mirroring the approach taken
when evaluating new drugs. The framework has separate stages
for theory, modelling and exploratory trial, with one following the
other. This has been very useful but Campbell and
colleagues (2)have suggested an alternative that
considers these three stages together and highlights their
iterative relationship. This approach has now been
taken in the modification to the MRC framework (3).
This framework, and other work (4), emphasises the need for a strong
theoretical foundation to inform both intervention development and
evaluation.. In this section of the manual, we have
followed Campbell and colleagues (2)
and the most recent MRC framework (3).
Firstly, NPT may also be adapted to guide the investigation of
the feasibility of whole interventions in advance of their
implementation, with the aim of providing a systematic and
comprehensive mapping of the human, organisational and resource
changes that an intervention will require. This is important
work because the implementation of some interventions is likely to
only be possible with major structural or organisational changes to
healthcare delivery. For example, thrombolysis for acute
ischemic stroke is likely to be effective in reducing later
disability but the treatment needs to be given within a few hours
of the first symptoms of the stroke. This might require a
major change in the way acute stroke is managed and in the way
clinicians treating stroke have to work. As one author
writing about this treatment put it 'Some neurologists are now
getting out of their beds in the middle of the night to go and see
patients - an activity that would have been almost unheard of a
short decade ago' (5).
Trials evaluating this sort of intervention might be called
'aspirational' because they assume a health care system that is
rather different from the one that currently exists. It would
be good to know up front that an intervention is aspirational
because trialists could, for example, start working early on with
policymakers and others to build support for making big changes if
the intervention proves to be effective. NPT could help to identify
aspirational interventions and allow trialists and others to better
judge whether the required changes are feasible on a wide scale and
whether the likely benefit of the intervention justifies making
them. The way you would use NPT in this way will be much the
same as for looking at intervention components i.e. use the NPT to
generate qualitative data with representatives of those affected by
the planned trial to consider normalisation issues
If the intervention if feasible, NPT could be used to aid the
design of the individual components of a complex
intervention. For example, there may be three potentially
effective components to a particular complex intervention. A
trialist could ask 'Should I include all of these components, or
just some?' The trialist could do a pilot study that
empirically tests each component individually and in combination,
which would be useful. However, potentially this would be time
consuming and costly. This is where NPT comes in.
NPT could be used by the trialist prior to such a pilot study
(or perhaps instead of if time and resources are limited) to
consider each potential intervention component in light of the
theory (see NPT Core Constructs). The
theory could be used by the trialist to guide analysis about the
likelihood of normalization of each of the three potential
components.
Using NPT for this sort of work could be done in a brainstorming
meeting, or through a series of focus groups, involving
representatives of those who would be affected by the
intervention. They would use their knowledge and experiences
to consider the likelihood of the potential components of interest
to the trialist. This is, of course, qualitative work and remember,
NPT can be used as a framework for the qualitative methods with
which you may already be familiar. See 'Qualitative
research' for ideas on how to do this.
As a result of the brainstorming meetings or focus groups,
representatives may highlight that a particular intervention
component is very likely, for example, to fall down because it
requires a lot of work to get people into using the new system of
practice, perhaps because it requires a lot of new training. An
intervention component that stands little chance of slotting into
normal, routine care for such reasons is likely to be less
appealing to policymakers considering use of the intervention in
their region, or to clinicians who are looking to improve aspects
of their own care provision than one that fits in more
easily.
As mentioned above, if resources allow, predictions coming from
this qualitative work could be tested in pilot work, which may now
involve fewer intervention components than originally planned
because some were rejected as a result of the NPT work.
Things to consider
- Describe in detail the intervention that you are
considering.
- Describe in detail who will be delivering the intervention
(e.g. the number, training, and experience of surgeons)
- Map the components of NPT to your intervention. Could
the design of the intervention be changed to improve its
chances of becoming normalized? How feasible is the
intervention given the current health care system, staff, training,
resources etc?
- Is your trial aspirational, or meant to evaluate an
intervention that can slot into an existing healthcare system?
References
- Medical Research Council
(2000). A Framework for Development and Evaluation of RCTs for
Complex Interventions to Improve Health. London, UK: Medical
Research Council. Back to text
- Campbell NC,
Murray E, Darbyshire J, Emery J, Farmer A, Griffiths F, Guthrie B,
Lester H, Wilson P, Kinmouth AL. Designing and evaluating
interventions to improve health care. BMJ 2007; 334: 455-459.
Back to text
- Craig P, Dieppe P,
Macintyre S, Mitchie S, Nazareth I, Petticrew M. Developing and
evaluating complex interventions: the new Medical research council
guidance. BMJ 2008:337:a1655 doi: 10.1136/bmj.a1655. Back to text
- Hardeman W,
Sutton S, Griffin S, Johnston M, White A, Wareham NJ et al. A
causal modelling approach to the development of theory-based
behaviour change programmes for trial evaluation. Health Educ Res
2005. Back to text
- Gubitz G.
The NINDS trials of thrombolysis in acute ischaemic stroke.
Practical Neurology 2002; 2: 45-49. Back to text
