Breakdown of key considerations used to determine IDEAL stage
| Characteristics of reports | Key issues addressed and content items | Key milestones for stage completion | |
| Idea (1) | One or very few reports Appears to be the earliest or near earliest report Only case reports or very small case series | States that this is first use in humans Detailed technical description | Reports an intervention not previously used in human |
| Development (2a) | Small number of reports Reports from one or a few centres All reports have small number of patients Nearly all reports are case Series | Safety of procedure Short-term outcomes Discusses indications Discusses technical detail and may describe modifications | Content and nature of reports suggest intervention technique has reached stability |
| Exploration (2b) | Increasing number of Reports Patients per report Centres involved Some prospective collaborative studies (registries, audits, databases) | Discusses procedural quality Discusses learning curves Comparison of outcomes with standard treatment Calls for an RCT to be done | Reports suggest that consensus has been reached on optimal technique, indications and outcome measures |
| Assessment (3) | Reports of multicentre RCTs Quasi-experimental designs Stepped-wedge designs Case-matching studies Analysis of large data sets with risk adjustment | Compares procedure with standard treatment | Reports document a high-quality RCT or other valid experimental comparison of the intervention compared with the current standard of care |
| Long-term (4) | Long-term cohort studies Retrospective case series Registries and databases Analyses of large administrative data sets No recent RCTs | Reports long-term outcomes Identifies rare outcomes May analyse risk or prognostic factors May report on changing indications | Ongoing reports of Late or rare outcomes Which patients benefit most Whether indications are changing Variation in performance |
RCT, randomised controlled trial.