Evaluating the Process of PPI: Lessons from the D-stress Study

Written by Jennifer Mohammadi, Research Assistant, King's College London's Faculty of Nursing, Midwifery & Palliative Care

When we talk about Patient and Public Involvement (PPI) in research, the focus

often falls on outcomes: What changed in the intervention? How did patient voices

shape the final product? These are important questions, but just as important is

understanding the process of involvement itself. How do we make sure contributors

feel valued, supported, and heard along the way? And what can we do to improve

how we do PPI in a project?

In the National Institute for Health and Care Research (NIHR) and Diabetes UK

funded D-stress study, which co-designed a diabetes distress intervention for people

living with type 1 diabetes (who formed a Patient Forum), we have placed equal

emphasis on evaluating how involvement happens as well as the differences the

Patient Forum made to the research. Here’s what we’ve learned.

Building Feedback Loops

At regular points throughout our co-design journey, we held structured reflective

sessions with our Patient Forum. These sessions were not about the research

content, but about the experience of involvement.

We asked questions like:

• How clear were the objectives of the latest workshop?

• To what extent did you feel your voice was heard?

• How accessible was the format and timing?

• What did you learn or gain from taking part?

  
  

By aligning these questions with the UK Public Involvement Standards, covering

inclusivity, working together, communication, impact, governance, and learning, we

created a framework for continuous improvement for how we went about our PPI

plans and activities.

Importantly, feedback wasn’t just collected. It was acted upon. Members could see

their comments reflected in visible changes, which built trust and reinforced that their

input mattered. One example was ‘creating space for connection.’

Creating Space for Connection

One of the clearest messages from our reflective sessions was that people wanted

more space to share their personal experiences and connect with each other.

Workshops were focused on adapting interventions and making decisions, but

members also valued the opportunity to simply talk as people with lived experience

of diabetes.

The solution came from the Forum itself: informal peer sessions held before

workshops, open only to those with lived experience. These provided a safe space

for storytelling and support, without competing with the co-design objectives of the

main sessions.

The impact was striking. By separating peer support from structured tasks,

workshops became more focused and productive, whilst members also felt more

connected and affirmed.

Making Involvement Visible

Another crucial part of our process was closing the loop, showing contributors how

their input had shaped the study. Too often, public contributors give their time and

ideas without ever seeing how those contributions are used. We wanted to make

sure that didn’t happen in D-stress.

At our final co-design workshop, we celebrated the progress from six earlier

workshops, reflected on the Forum’s influence, and showcased the final design.

Researchers demonstrated the concrete changes that had come directly from

Patient Forum input.

Members could literally see their words in the materials. One said, “I saw a key

phrase I’d used appear in the final content.” Another reflected, “It was really powerful

and valuable … it made my investment of time worthwhile.”

Closing the loop made involvement visible and meaningful. It showed respect and

accountability, built trust, and confirmed that contributions were integral to the

research, not tokenistic. For Forum members, it created a sense of ownership and

pride in the work, knowing their fingerprints were clearly on the final outcome.

Process as Impact

Through these practices, we’ve seen that evaluating PPI is not only about tracking

what changes in the research. It’s also about asking:

• Did people feel respected?

• Was their time used well?

• Were there opportunities for connection and growth?

Our reflective sessions, peer spaces, and commitment to closing the loop showed

that the process itself generates impact, by building confidence, creating community,

and making involvement genuinely inclusive.

Looking Forward

As we continue the D-stress study, we will keep refining our approach through

ongoing reflective sessions and annual meetings with the Patient Forum. Our

commitment is to keep process evaluation at the centre, because without it,

involvement risks becoming tokenistic.

By listening, adapting, and closing the loop, we can ensure that PPI is not only about

shaping better research, but also about building better experiences for the people at

its heart.

Watch Jennifer's webinar on Evaluating PPI in Research here.