# Supporting public involvement in defining estimands: a practical tool accessibly explaining the five key attributes of an estimand

## TL;DR

This paper introduces a tool to help researchers and the public understand and define research goals in clinical trials using accessible language.

## Contribution

The paper introduces a co-developed practical tool that explains the five attributes of an estimand using accessible language for public involvement.

## Key findings

- A tool was co-developed with public partners to explain the five attributes of an estimand using accessible terms.
- The tool was refined through feedback from diverse public partners and is available for use in trial planning.
- The tool can also assist researchers unfamiliar with the estimand framework.

## Abstract

An estimand is a precise description of the treatment effect a trial is aiming to find out. We previously identified that public partners (defined as patients and/or members of the public who are part of the research team) want to be involved in establishing estimands during trial planning. This involvement helps to ensure that trials address the questions that matter most to patients and the public. To initiate this, we co-developed a tool with public partners to help researchers explain the concept of an estimand in an accessible way. However, for public partners to be actively involved in defining estimands, the scientific terms used to describe the five attributes of an estimand must be further broken down. Accessible terms to describe estimand attributes would also be of benefit to researchers who are new to the estimand framework. Therefore, we aimed to co-develop with public partners an additional practical tool to clearly describe these five attributes and facilitate their understanding.

An online consultation meeting followed by an in-person workshop was held with 5 public partners of mixed age, gender and ethnicities, from various regions of the UK. Public partner opinions were collected, and the newly proposed accessible terms to describe the attributes of an estimand were developed. Afterwards, the proposed accessible terms were presented to an independent wider patient and public involvement and engagement group with 15 public members at an online meeting. The accessible estimand attribute terms were refined and additional feedback sought via email.

A tool explaining the 5 attributes of an estimand, accessibly referred to as the 5 pillars of the research question, was created incorporating the public partner feedback.

We provide a co-developed tool for researchers and public partners to use to facilitate the involvement of public partners in devising estimands. The tool explains the 5 attributes of an estimand using accessible terms proposed by public partners. It can be used in conjunction with the previously developed tool, which introduces what an estimand is and why it matters, to facilitate discussions with public partners on defining estimands during trial planning. The tools can also be used by other stakeholders including researchers unfamiliar with the estimand framework and those who find the scientific estimand attribute terms inaccessible.

The online version contains supplementary material available at 10.1186/s13063-025-08941-4.