Impacts on subjective wellbeing, mental health, and pro-sociality are large: the course
increases life satisfaction on a zero-to-ten scale by about one point, more than being partnered
as opposed to being single (+0.6) or being employed as opposed to being unemployed (+0.7)
(Clark et al., 2018). It is more than double the effect of ENHANCE, a 12-week course focusing
primarily on positive habits, skills, and attitudes, which is probably the most comparable
intervention (Kushlev et al., 2017). 28 However, the authors are able to track outcomes over a
longer period of time, up to six months post-treatment. Finally, the effect on life satisfaction is
somewhat larger than effects found in trials by the UK Big Lottery Fund, which funded a wide
range of wellbeing programmes (fourteen portfolios, each consisting of three to 34 actual trials)
from 2008 to 2015 at a volume of £200 million. Trials typically included community-based
activities such as horticultural activities, cooking lessons, or sports events. As a conservative
estimate, they increased life satisfaction on a zero-to-ten scale by, on average, 0.5 points for six
months post-treatment (New Economics Foundation-Centre for Local Economic Strategies,
2013). Different from our intervention, however, these trials all targeted specific groups with
mental health needs, including overweight adults, families with young children, or people with
substance use disorders.
As far as comparisons, they say: