The DECODE Project

Developing Consensus Core Outcomes and Diagnostic Criteria for Otitis Externa

Identifying the most important factors in the care and patient experience of outer ear infections

Please click on the following links to view the Study Protocol and Patient Information Sheet.


Frequently Asked Questions

1. What is a Delphi process?

Also known as a Delphi method, technique or survey, this is a research process where a group of experts in a field respond to a series of questionnaires in order to reach a group decision. The responses are shared with all panel members after each round of the questionnaire.


2. What is a Core Outcome Set?

A Core Outcome Set is a set of recommendations on what research in a particular area should be measuring and reporting on.

In this project, we aim to use the Delphi method to identify which factors in otitis externa are the most important to report on when conducting research in this field. This would enable clinicians and researchers to compare and combine results from different studies.


3. How were the questions I will be asked devised?

The results from structured patient interviews and from a systematic review of published research in otitis externa informed the questionnaire design as described below.

  1. Patient Interviews

Our team developed six specific questions to gather information about patients’ experiences of their care related to otitis externa, their experiences of being affected by this condition and their ideas regarding priority areas for future research.

Nine patients representing a range of ages and backgrounds were interviewed once their treatment was complete and their otitis externa resolved, and the results of these interviews were kept anonymous. We identified key themes from these interviews according to guidelines on Core Outcome Set development (

  1. Systematic Literature Review

Published research from 2007 to 2018 looking at the effectiveness of treatment for acute otitis externa in adults was reviewed by our team to identify relevant studies. This date range for studies was carefully selected in line with guidelines on Core Outcome Set development ( From the relevant studies, key information about the diagnosis of otitis externa and the reported outcomes including patient-reported outcome measures was identified.

Key factors identified from patient interviews together with those identified from the literature review were combined by our research team. These results are the basis of questions you will be asked to ensure that both patient perspectives and scientific research are represented in developing this Core Outcome Set.


4. Who will be participating, and why have these participants been invited?

A total of 140 healthcare professionals, and patients who have experienced otitis externa have been invited to participate. The professional stakeholders have been carefully selected based on their clinical involvement with patients with otitis externa, with a higher proportion of those with direct clinical contact represented.

The professional groups include: consultant general ENT surgeons, consultant otologists, ENT junior doctors and specialist nurses, general practitioners, microbiologists, paediatricians and Audiologists and represent a number of areas across the UK.

Only professional stakeholders will be asked to complete survey questions relevant to diagnostic criteria, and these domains include Mortality, Pathophysiology, Infection, and Pain. All stakeholders will be asked to respond to questions regarding additional domains, including Quality of life, Mental health, Psychosocial wellbeing, Functioning and daily activities, Compliance with or withdrawal from treatment, Satisfaction, Resource use and Adverse events.

All stakeholders are requested to complete each of the three survey rounds.