Expert estimation in screening

The text on this page is taken from an equivalent page of the IEHIAS-project.

Expert estimation is a valuable (and often powerful) method for doing screening, in order to determine whether a full integrated impact assessment is appropriate. Its value comes, especially, from the fact that:

• It can make use of a wide range of experience and knowledge, including unpublished evidence;
• It is relatively quick and inexpensive to organise;
• It is a formative as well as summative process – it provides insight into the assessment (e.g. in the form of comment from participants) and therefore can help to shape and plan the actual assessment.

In general terms, expert estimation involves surveying a group of people, with proven understanding of the topic, in order to derive some form of opinion about the likely importance and magnitude of the health impacts. There are many different ways of carrying out such surveys, including through the use of:

• informal and formal meetings, including brainstorming and focus group meetings;
• questionnaire or interview surveys;
• internet-based collaboration (e.g. using Opasnet).

Further information on the use of Delphi surveys is provided via the link in the panel to the lfet, and a wide variety of methods are summarised on the Joint Research Centre's FOR-LEARN website. In each case, however, it is important to ensure that:

• the participants have genuine expertise relevant to the issue of concern, preferably based on research experience;
• the participants provide reasonably balanced coverage of the issue, and are not biased to particular aspects (e.g. exposure modelling, epidemiology, toxicology) or to particular schools of thought;
• the consultation process requires justification of all opinions and statements (e.g. by reference to theory, observations or experiments);
• the process provides opportunity for open feedback and comment;
• the methods and results of the survey are open to scrutiny by stakeholders involved in the assessment.

Links to a detailed protocol on the design and organisation of expert elicitation methods, and a worked example on estimating exposure-response functions for ultrafines, are also given under See also.

See also

• File:Protocol on Expert Elicitation 0.pdf
• Case study on ultrafine particles
• Expert elicitation methodology
• Delphi surveys