INCLUDE was a mixed-methods cross-sectional observational study embedded in, and forming a discrete component of, the ongoing longitudinal ‘Improving the experience of Dementia and Enhancing Active Life’ (IDEAL) cohort. INCLUDE comprised 172 people with dementia and 288 carers living in England and Wales. People with dementia residing in care homes could not be contacted to take part so only community dwelling people with dementia took part in INCLUDE. Interviews with people with dementia were carried out over the telephone or via videoconference. All responses were recorded by researchers using an online survey designed in Qualtrics. Carers were either interviewed in a similar way or self-completed an online form in their own time. Data were stored in Qualtrics. Structured assessments with all participants were conducted remotely due to COVID-19 restrictions between September 21, 2020, and April 30, 2021. For people with dementia, interviews began with questions about health and healthcare during the pandemic, and subsequent sections covered perceptions of social connection and relationships, psychological health, ability to manage everyday life during the period, and overall perceptions of the capability to ‘live well.’ Carers were asked to provide informant reports and describe their own experiences. The questions for carers covered health, social networks, psychological well-being, and caregiving experiences. In addition, people with dementia and carers who were both willing and able to participate in a semi-structured interview were identified, and interviews were conducted remotely between November 2020 and January 2022. Three sets of interviews were conducted, totalling 51 interviews. In the first set, eighteen interviews were conducted representing 21 participants: 8 were with people with dementia, 7 were with carers and 3 were joint interviews, i.e., the person with dementia and carer were interviewed together. In the second set, fourteen interviews were conducted representing 15 participants: 7 with people with dementia, 6 with carers, and 1 joint interview. For the third set, participants had previously been interviewed either for one of the two sets of INCLUDE in-depth interviews or for an earlier IDEAL sub-study conducted at the start of the pandemic, the IDEAL COVID-19 Dementia Initiative (IDEAL-CDI). In the third set, nineteen interviews were conducted: 9 with people with dementia and 10 with carers. Of the people with dementia interviewed in this third set, 6 participants were from INCLUDE set 1 interviews, 2 from INCLUDE set 2 interviews and 1 from IDEAL-CDI. Of the carers interviewed in this third set, 6 participants were from INCLUDE set 1 interviews, 3 from INCLUDE set 2 interviews and 1 from IDEAL-CDI. It must be noted that the IDEAL-CDI interviews are not archived, and the data is not currently available.INCLUDE was a mixed-methods, cross-sectional observational study embedded in, and forming a discrete component of, the ongoing, longitudinal ‘Improving the experience of Dementia and Enhancing Active Life’ (IDEAL) cohort study. The 10-year IDEAL programme centres on a longitudinal cohort study of people with dementia and family carers (hereafter ‘carers’) across Great Britain. The IDEAL programme has two phases, IDEAL (2014 – 2019) and IDEAL-2 (2018 – 2023). IDEAL was funded by the Economic and Social Research Council and National Institute for Health Research and IDEAL-2 was funded by Alzheimer’s Society as a Centre of Excellence. INCLUDE added a COVID-19-specific data-collection module to the planned follow-ups of the cohort in IDEAL-2. The study was co-ordinated by the Centre for Research in Ageing and Cognitive Health (REACH) at the University of Exeter Medical School. Involvement of people with dementia and carers is central to the IDEAL programme. The ALWAYs (‘Action on Living Well: Asking You’) group of people with dementia and carers was set up to ensure meaningful involvement. The involvement of people with dementia and carers ensured that the study processes, materials, and emerging outcomes were clear and relevant. The ALWAYs group advised on the design and content of the INCLUDE surveys. INCLUDE aimed to identify the impact of COVID-19 and resulting physical distancing measures on PwD and their carers. The goals of INCLUDE were as follows: 1. To identify the impact of COVID-19 on people with dementia and carers. 2. To understand reciprocal dyadic influences. 3. To build on this evidence to create resources to support the social, mental and physical health, and relationships of community-dwelling people with dementia and carers and provide guidance to health, social care, and voluntary sector staff. The INCLUDE sample comprised 172 people with dementia and 288 carers living in England and Wales, all of whom completed individual structured interviews. Interviews took place between September 21, 2020, and April 30, 2021, and were conducted remotely due to COVID-19 restrictions. For people with dementia, interviews began with questions about health and healthcare during the pandemic, and subsequent sections covered perceptions of social connection and relationships, psychological health, ability to manage everyday life during the period, and overall perceptions of the capability to ‘live well.’ Carers were asked to provide informant reports and describe their own experiences. The questions for carers covered health, social networks, psychological well-being, and caregiving experiences. People with dementia could take part if there was no carer taking part, and carers could take part if the person with dementia was no longer willing or no longer able to take part. Where a person with dementia also had a carer taking part in the study, their study identification numbers are the same, and therefore the data can be linked. In addition, a sub-group of participants who were both willing and able to participate in a semi-structured interview was identified, and these semi-structured interviews were conducted remotely between November 2020 and January 2022. A total of 51 interviews was conducted over three waves of interviewing at different stages of the COVID-19 pandemic. The number of people with dementia and carers interviewed at each wave is outlined in the user guide. Working together with people with dementia and carers, we have used the evidence gained to develop the Living with Dementia Toolkit “https://livingwithdementiatoolkit.org.uk/”, a set of resources to support social, mental and physical health, and relationships for people with dementia and carers, and provide guidance for health, social care, and voluntary sector staff. At the time of writing, five scientific journal articles have been published using the quantitative and qualitative data. These have focused on the impact of the COVID-19 pandemic on people with dementia and carers. These publications are available from the IDEAL programme website “https://www.idealproject.org.uk/activities/papers/” and additional publications will be added there as they become available.

INCLUDE added a COVID-19-specific data-collection module to the nationwide IDEAL-2 study. INCLUDE participants were people with dementia and carers who took part in IDEAL and IDEAL-2. All participants who took part during IDEAL data collection timepoint 3 or who had taken part in IDEAL-2 timepoint 4 were contacted. In total, 624 eligible people with dementia and 584 eligible carers were identified. Of these, 109 people with dementia and 88 carers could not be contacted. Of the remaining 515 people with dementia and 496 carers, 343 people with dementia and 208 carers did not participate. In total, 173 people with dementia and 288 carers took part in INCLUDE. One person with dementia was subsequently removed from the dataset after being rediagnosed with a different condition. The final number of participants with dementia was therefore 172. There were no specific inclusion criteria as all participants were already taking part in the IDEAL programme; however, people with dementia were excluded if they lacked capacity to provide informed consent. No new participants were recruited into the study, except that in five cases a different family carer replaced the carer who had previously contributed. People with dementia could take part if there was no carer taking part, and carers could take part if the care recipient was no longer willing or no longer able to take part. People with dementia residing in care homes could not be contacted to take part so only community dwelling people with dementia took part in INCLUDE. All interviews were conducted remotely due to COVID-19 restrictions. All participants completed the structured interviews, and 36 participants (19 people with dementia and 17 carers) also completed in-depth semi-structured interviews. The structured interviews included brief measures and items from validated scales used in the IDEAL study, and bespoke questions focusing on experiences during the pandemic, and some additional open-ended questions offering opportunities to expand on specific responses. For the semi-structured interviews, a topic guide was prepared based on questions and prompts that were open-ended to allow for flexibility to reflect on different experiences. Detailed information about the INCLUDE sample characteristics for the structured and semi-structured interviews can be found in the User Guide. A list of measures, interview schedules, and surveys can be found in the Data and Interview documents.