The IDEAL Framework

The IDEAL Framework describes the stages through which surgical therapy innovation normally passes, describing the characteristics of each of five stages:  Idea, Development, Exploration, Assessment and Long-term follow-up.

This page outlines the five stages of the IDEAL Framework.  From each stage you can link to the relevant Checklist, and you can download more resources using the Resources panel in the sidebar.

Thought Cloud

Stage 0 – The Preclinical Stage

Deals with the evaluation of a medical device prior to first-in-human stage 1 studies.

On the one hand, any first-in human studies carry obvious risks. On the other hand, only 10% of medical devices make it from development to stage 1. Stage 0 provides a framework for robust and transparent evaluation of devices, following the principle that the more invasive and high risk a device is, the greater proof required of their safety and effectiveness before progression to clinical studies.

Stage 0 Checklist

Stage 1 - Idea

Deals with proof of concept, involving first use in humans.

At this stage, evaluation describes the new intervention in its first live demonstration: what it is, how it works and what the first experience taught us.

Stage 1 Checklist

Stage 2a - Development

The technical details are refined and stabilised through experience in a small case series.

Evaluation records the iterative improvement of the intervention until it reaches a stable form. What was changed, when, why and with what impact on outcomes?

Stage 2a Checklist

Stage 2b - Exploration

A common understanding of the procedure is reached among operators in a multi-centre study, and the obstacles to a definitive comparative trial are addressed. The goal of this stage should be to prepare better for a pivotal evaluation against best current therapy.

Evaluation focuses on defining the intervention, its indications and the standards for acceptable quality of delivery, by collaborative prospective cohort study by multiple groups, including analysis of learning curves.

Stage 2b Checklist

Stage 3 - Assessment

Typically a randomized controlled trial (RCT).

Evaluation of the intervention against current practice is now possible, preferably in an RCT. Mechanisms to neutralize effects of any deficit in investigator equipoise are important.

Stage 3 Checklist - CONSORT
Long term study

Stage 4 - Long-term study

Surveillance to identify rare and late outcomes as well as a possible broadening of ‘accepted’ indications.

Evaluation involves large-scale surveillance of outcomes in routine use of the intervention, looking for trends, or unexpected, late or rare side effects.

Stage 4 Checklist

An introduction to IDEAL, with paper planes

In this 20-minute workshop video, Peter McCulloch works with a team to illustrate the Stages of the IDEAL Framework, using paper aeroplanes.

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First publication in the Lancet

The IDEAL Framework was first published in the Lancet in 2009 ( McCulloch et al, Lancet 2009; Sep 26; 374 (9695): 1105-12.).  You can access the full text from the Resources bar on this page, or read the Abstract below.


Peter McCulloch, Douglas G Altman, W Bruce Campbell, David R Flum, Paul Glasziou, John C Marshall, Jon Nicholl, for the Balliol Collaboration

Surgery and other invasive therapies are complex interventions, the assessment of which is challenged by factors that depend on operator, team, and setting, such as learning curves, quality variations, and perception of equipoise.

We propose recommendations for the assessment of surgery based on a five-stage description of the surgical development process.

We also encourage the widespread use of prospective databases and registries. Reports of new techniques should be registered as a professional duty, anonymously if necessary when outcomes are adverse.

Case  series studies should be replaced by prospective development studies for early technical modifi cations and by prospective research databases for later pre-trial evaluation.

Protocols for these studies should be registered publicly.

Statistical process control techniques can be useful in both early and late assessment. Randomised trials should be used whenever possible to investigate efficacy, but adequate pre-trial data are essential to allow power calculations, clarify the definition and indications of the intervention, and develop quality measures.

Difficulties in doing randomised clinical trials should be addressed by measures to evaluate learning curves and alleviate equipoise problems. Alternative prospective designs, such as interrupted time series studies, should be used when randomised trials are not feasible.

Established procedures should be monitored with prospective databases to analyse outcome variations and to identify late and rare events.

Achievement of improved design, conduct, and reporting of surgical research will need concerted action by editors, funders of health care and research, regulatory bodies, and professional societies.