The Department of Health (DOH) is considering funding a new intervention to reduce loneliness in community-dwelling older adults aged 65 years and above. To evaluate the effectiveness of the new intervention, called "Friends next door", a randomised control trial will be conducted. Friends next door has been designed to improve older adults' wellbeing and alleviate loneliness by enhancing current friendships or developing new friendships. The intervention consists of 12 weekly lessons that focus on topics related to friendship (e.g., expectations of friendship, making new friends, improving existing friendships). Each lesson is supplemented by practicing skills, role playing, and a homework assignment. The lessons are delivered to a group of 8-12 older adults by a trained psychologist in education or community centres. The trial will recruit community-dwelling older adults aged 65 years and over who experience loneliness. Participants will be randomized to the intervention group or the control group and followed-up for six months. The DoH wants to know whether the new intervention, Friends next door, represents good "value for money". The DoH is also considering investing in a new depression prevention intervention for older adults, which has a cost effectiveness ratio of $30,000/QALY. Unfortunately the DoH does not have the resources to invest in both interventions. You are part of a research team that has been asked to design a protocol for an economic evaluation alongside the clinical trial. Your role in the team is to answer the following:

What type of economic evaluation do you think will be the most appropriate for answering your study question? Justify why you have chosen this method for your economic evaluation explaining its strengths over other methods.

CEA, CUA or CBA ?