At present, in Scotland, in order to become an organ or tissue donor after death, a person must either have expressed a wish/decision to do so or one of their relatives can authorise donation on their behalf. This system is known as an ' opt in' system. In many cases, individuals make their decision known by joining the NHS Organ Donor Register ( ODR). If an individual has not given authorisation and they could be a potential organ or tissue donor, their nearest relative will be asked to make a decision. However, a nearest relative cannot authorise donation if they know that their relative did not want to donate. Having such sensitive conversations with families at the time an individual dies is very difficult, and, understandably, many families find it impossible to consider such requests when they are often in shock or grieving. In such circumstances a significant minority of families (43.6% in 2017-18) do not give authorisation for donation for transplantation, although survey evidence suggests that the majority of people in Scotland support donation.
Conversely opt out systems presume (or deem) that a person consents to becoming a deceased donor if they haven't actively opted out of donating e.g. by joining an opt out register or otherwise making their decision clear. In a hard opt out system, family members are generally given little if any input to the decision, but most opt out systems have some form of safeguards to allow families to say if they don't think their relative wished to donate – this is known as a 'soft' opt out system. A number of soft opt out systems also exclude certain categories of people, such as children, from being covered by the presumed consent arrangements.
In Wales, a soft opt out system of deceased organ and tissue donation was implemented in December 2015. This continues to allow for potential donors to provide consent themselves, for example by joining the ODR or for a relative to provide consent on their behalf. It also provides for a statutory 'opt out' ODR of people who do not want to donate their organs or tissue. Where an individual has neither opted in nor opted out then their consent can normally be deemed. However, this is subject to certain safeguards, for example checking that family members are not aware of the potential donor having said to anyone that they did not want to be a donor. In addition, children, adults with long-term incapacity and people ordinarily resident in Wales for less than twelve months cannot have their consent deemed.
In England and Northern Ireland, the existing legislative system under the Human Tissue Act 2004 is an opt in system, which is very similar to that in Scotland. However, the UK Government has indicated that it is supportive of proposals to move to an opt out system for England and is expected to publish its response to the recent consultation on opt out shortly. This means that an opt out system may also be implemented in England in the future. There are no current known plans to move to an opt out system in Northern Ireland.
In Scotland, since 2013/2014 there has been an 18% increase in people registering a decision to become a donor after death and the percentage of people on the ODR in Scotland is the highest in the UK (48% as at June 2018  ) ( NHS Blood and Transplant , 2017). Survey evidence  suggests that the Scottish public are generally supportive of the principle of opt out. Evidence from the wider UK suggests that support for opt out has been growing over time and is now supported by the majority of the population (Rithalia, et al., 2009). This is further discussed in section 4.6.
This review was undertaken to provide an overview of evidence to inform decision making concerning opt out and its potential implementation.
The overarching aim of this rapid evidence review is to explore the evidence of effectiveness of opt out organ donation legislation and systems  .
Specifically it aims to examine evidence regarding:
- the effectiveness of opt out legislation and systems in increasing the number of transplants and donations
- contextual factors that are likely to influence organ donation and transplantation
- other non-legislative factors that are positively associated with successful opt out systems and higher rates of organ donation independently of opt out (infrastructure, public awareness/attitudes, family authorisation, staff attitudes and awareness, media campaigns and support for organ donation)
- the potential influence religion and ethnicity could have on opt out.
There is a particular focus on evidence from Wales because it is more comparable than many other countries that have adopted opt out legislation and systems.
A literature search was conducted by the Scottish Government Library and covered a wide range of resources, including: IDOX; K&E; Web of Science; and ProQuest Databases. The majority of the literature was published within the last few years. Both peer reviewed and non-peer reviewed (grey literature) papers were considered. This was partly due to limited evidence base regarding the impact of opt out. This paper considers much of the research covered in a systematic review for the Welsh Government and also more recent evidence, such as international comparative study by Shepherd et al (Shepherd, et al., 2014).
This paper was peer reviewed by researchers external to Scottish Government at NHS Health Scotland.
The review was completed in a short timescale, and consequently it is not intended as an exhaustive critical appraisal of the research evidence. There are limitations to the current evidence base which are highlighted throughout. For instance, many international studies do not distinguish between hard and soft opt out systems and their impacts despite the substantial differences in the importance of family views/consent. This limits the extent to which we can generalise these findings to the potential implementation of opt out in Scotland. In addition, there was often a lack of specific evidence with regards to opt out. In this case, inferences have been made from the wider organ donation literature. In the literature that examined the influence of other factors in increasing donation and transplantation, it was often unclear what the most crucial factors were.
A lack of evidence was identified with regards to tissue donation and transplantation and therefore it has not been considered specifically in this review.