The National Statement says that you should respect people's capacity to make their own decisions. This normally means that people should give express consent to take part in your project.

Sometimes it may be justifiable to use an alternative approach. You may be able to use an opt out approach or a waiver of consent. This might be appropriate if you are running a large scale, low risk project and it is not feasible to get express consent from each person.

Using an opt out approach means that participants are included in the research unless they give their express decision to be excluded. Their decision must be informed. Therefore, you still need to give them information about your project. Once you have done this, you can assume that they are willing to take part in your project unless they say they do not want to. 

If you want to use an opt out approach, you must get permission from a Human Research Ethics Committee. You need to make a strong argument that:

1. your project poses little or no risk to participants and
2. the risk of not seeking express consent is outweighed by the public benefit or interest of the research.

This is only appropriate if people can make an informed choice about participation. This requires that:

• you give people written information about the project
• people receive this information, and are able to read and understand it
• people are able to act on the information to decline participation.

It may be appropriate for you to use different types of consent for different parts of your project. For example, you might seek explicit written consent for participation in clinical research. You might then use an opt out approach if you are seeking to use people’s information as part of a registry.

The opt out approach is unlikely to constitute consent if you are applying Commonwealth privacy legislation to the handling of sensitive information, including health information. In some cases, it may not be feasible for you to get a participant’s explicit consent to use their information, but you cannot achieve the purpose of your research by using non-identifiable information. In these cases, you must comply with the guidelines under section 95 or section 95a of the Privacy Act 1988. If you are seeking to use an opt out approach to which sections 95 or 95a apply, only a HREC can grant this approval.

For more information about an opt out approach, see Chapter 2.3, 2.3.5 - 2.3.6 of the National Statement.

If you are using the opt out approach, this template letter will help you write your own letter to participants.