Implementation Secrets Part 3: putting improvement cycles into practice and the importance of fidelity to function


by Kristian Hudson

Kristian Hudson is an implementation specialist with the Yorkshire & Humber Improvement Academy working with researchers and practitioners across the Yorkshire & Humber Applied Research Collaboration.

Implementation scientists argued for a long time that in order to implement complex interventions well and for them to get the expected outcomes, they must be used in the same way as the designers intended i.e. there must be ‘fidelity to form’. But what an improvement approach allows for is for people in the setting to make changes to the intervention so it works better for them. 

They adapt the intervention to emerging issues and through improvement cycles keep on doing this over time. So, if a group of scientists develop a new exercise programme for stroke in-patients and show is works through a series of randomised controlled trials, a more traditional approach would insist that anyone using that programme must deliver exactly the same form of that programme. There might be instructions and written information for patients to read, there will likely be training materials for staff, the dosage will be set at a certain amount (e.g. 10 minutes of exercises a day), and the best time of day might be suggested.

All these aspects are part of the intervention’s ‘form’ and, up until recently, implementation scientists would often argue that unless there was fidelity to form there would not be good implementation outcomes (Durlak & DuPre, 2008). Wind on 15 or so years and there is now good evidence that adapted interventions can achieve stronger effects than non-adapted interventions (Hasson, Sundell, Beelmann, & von Thiele Schwarz, 2014; Leijten, Melendez-Torres, Knerr, & Gardner, 2016). 

Allowing for adaptation in situ avoids the voltage drop. The intervention keeps its effectiveness over time. It remains functional. Adaptation can also ensure people are reached who might not have been had no adaptation taken place (Burrow-Sánchez, Minami, & Hops, 2015). Imagine there are some people who are blind on the stroke ward, or who do not speak English? Maybe the healthcare team already have a time in the day when they attempt to get patients up and moving. 

Instead of focussing on the form of the programme, staff can be encouraged to focus on the ‘function’ and keep fidelity to that. The medical research council, until recently, acknowledged that the more complex an intervention the harder it will be to implement. They labelled ‘complex interventions’ as those with the most parts. They didn’t offer any other guidance but more recently they have started to come round to the idea of fidelity to function over fidelity to form: 

standardisation may relate more to the underlying process and function of the intervention than on the specific form of the components delivered” (Medical Research Council, 2018) 

And the Health Foundation also commented recently in its white paper that “Traditional approaches to spreading innovation, tend to assume that once an innovator has developed an idea and successfully piloted it, it can then be ‘diffused’ and taken up by others in a straightforward way. By contrast, we argue that reproducing a complex intervention at scale is a much more distributed effort, often involving a good deal of creativity and reinvention from those taking it up, with the intervention itself sometimes undergoing substantial revision and refinement in the process” (Health Foundation, The Spread Challenge. Horton, Illingworth & Warburton 2018 p.7).

Putting cycles into practice

Putting all this into practice is an exciting prospect. In one of my later podcasts I was lucky enough to speak with Deon Simpson from the Dartington Service Lab. Dartington have developed an approach to applying both implementation science and improvement science to child welfare projects out in the community. They call this Rapid Cycle Design and Testing and trialled this approach with Chance UK, an award-winning early intervention children’s charity founded in 1995 who through mentoring aim to help children feel happy about themselves, realise their potential, and be confident in their ability to build a brighter future. Dartington was able to introduce their Rapid Cycle approach to Chance UK who successfully moved through a number of rapid cycles addressing implementation issues and improving the form of the intervention along the way.

This sort of approach has also been demonstrated in Yorkshire and Humber by the Improvement Academy. I interviewed Dr Ali Cracknell, Dr Elizabeth Taylor-Buck and Amanda Lane. They have had a great deal of success implementing their interventions by ensuring a high degree of clinician and service user input. They tend to avoid top-down mandating, there is no over strict push for fidelity to form, and they encourage adaptations and optimisation by teams over time. They make sure there is a clear theory of how the intervention is meant to work.

The result was that Dr Ali Cracknell and the Improvement Academy implemented sustainable and effective safety huddles into 70% of hospital wards. A safety huddle is a short multidisciplinary briefing, held at a predictable time and place, and focused on the patients most at risk (Goldenhar, Brady, Sutcliffe, & Muething, 2013). 

Effective safety huddles involve agreed actions, are informed by visual feedback of data and provide the opportunity to celebrate success in reducing harm. But Dr Cracknell and the Improvement Academy didn’t implement huddles using a traditional top-down mandated approach or something based on RCT trials. Instead, they introduced the concept of huddles to an initial receptive team, and after ruling out harm, they then started collecting data on effectiveness and working out the key ingredients of the intervention that made it successful over time, while allowing teams to adapt the intervention to fit their needs. They learnt from early adopters that huddles didn’t have to be exactly the same to achieve the same results – which were significant increases in team safety culture and patient safety.

The ReQoL team (Taylor-Buck and Lane) took a similar approach and ensured a high degree of service user and clinician input in the design of their patient outcome measure. They held stakeholder workshops and engaged clinicians, managers, commissioners to take ReQoL out of the academic arena and put it into the practical arena. They used an advisory group to help with the knowledge transfer. The result was getting ReQoL into 80% of Trusts.

The contribution of practitioners to effective implementation has been highlighted in the early stages of the recent pandemic. Michael McCooe, an Intensive Care Unit consultant and Clinical Director of the Yorkshire & Humber Improvement Academy described how when clinicians were given more decision-making power on their ward during the pandemic, overall implementation was far better. David Melia, the executive nurse and deputy chief executive for Mid Yorkshire Hospitals NHS Trust believes that frontline staff have more autonomy than they realise and suggested that there is a role for executives and managers to encourage frontline staff to use that more.


Implementation is a complicated business and the voltage drop is an ongoing issue. We have got very good at analysing the problem of implementation but we need to get better at knowing the all important ‘how to’ if we are to ensure interventions benefit society. Knowing ‘how to’ seems to have something to do with empowering and supporting practitioners to adapt interventions to overcome implementation issues as they emerge in their setting. 

When they do this the voltage drop can be decreased or avoided and many of my podcast guests have experienced this. If implementation specialists can train teams in improvement science methods like this they will also be decreasing the gap between implementation science and implementation practice which is a good thing for implementation science long term. 

People who specialise in implementation science are in a good position to do this. They are also the people who might best be able to persuade organisations to create implementation environments that foster bottom-up rather than top-down implementation.

Good luck in your implementation!

If you would like to know more about implementation or have a project in mind get in touch with us.


A big thank you!

I would like to thank Beverley Slater and everyone else at the Improvement Academy who has helped me put this blog together. I would also like to thank all the wonderful participants on my podcast whose knowledge has been priceless in me creating this blog and understanding implementation further.

Contact for more information:

Kristian Hudson

Implementation Specialist at the Improvement Academy

Bradford Institute for Health Research

I work at the Improvement Academy in Yorkshire, England, UK. We are a team of implementation scientists, improvement scientists, patient safety experts and clinicians who work with frontline services, patients and the public to deliver real and lasting change. Check out our website at

Related Blogs

Taking Steps Towards Equality, Diversity, and Inclusion in Yorkshire & Humber ARC Research

We want all people and communities in YH to benefit from our research. To do this we aim to follow best practice and have the highest standards of equality, diversity and inclusion in all our research. The NIHR Applied Research Collaborations (ARCs) are leading efforts to put the latest NIHR Equality Diversity and Inclusion (EDI) Strategy into practice within their research programs. Some ARCs have developed toolkits while others have developed strategies focused on "mainstreaming" EDI.

Patient and Public Involvement (PPI) on a pain and frailty study – reflections on involvement, engagement, and impact 

The The YH ARC supported Pain in Older People with Frailty (POPPY) Study is a 3-year NIHR-funded study hosted by Bradford Teaching Hospitals NHS Foundation Trust (commenced April 2022). The study aims to provide service guidance to improve access and support for older adults living with frailty to better manage their pain.

Implementation researchers’ perspectives on bridging the research-practice gap

In our blog earlier this year, we talked about simplifying implementation science, and making it more accessible to frontline staff. In this blog we will share critical insights that the implementation team, based at the Improvement Academy, has gathered while supporting, and facilitating putting evidence into practice.