The effect of intervention on individual health: application of methods to analyse heterogeneity of treatment and heterogeneity of treated.

This Fellowship attempts to determine the effects of a large primary health care policy, namely the Quality and Outcomes Framework (QOF), on health behaviours and mental health conditions for a representative sample of the older population in England. The QOF was introduced in April 2004 and has provided substantial incentives for practices to treat and manage specific conditions, including mental health and cardiovascular diseases. I will explore how impact of this policy varies across the population and whether this is attributable to different treatment quality provided by primary care practices and/or different characteristics of the treated individuals.
The causal mechanisms by which health care impact upon health behaviours and mental health are complex. For instance, a health care policy aiming to reduce smoking might have spillover effects onto other health behaviours. Therefore, the aim is to relate clusters of health interventions (either be medical treatment or lifestyle advice) to clusters of health behaviours (i.e. smoking, drinking and physical activity) and to mental health conditions.
The magnitude of such mechanisms could depend on two factors. First, they could be affected by the differential quality of treatment provided by health care practices (i.e. the likelihood to offer smoking cessation advice to the population of smokers). Second, they could be related to different socioeconomic characteristics of the treated individuals (i.e. by their cognitive abilities or the severity of their debt problems).
Health behaviours are particularly important in determining the health status of the population in the U.K. where chronic diseases are a major cause of morbidity and mortality. Mental illness is the largest single cause of disability in the U.K. The focus on an older population is important because as individuals age, they enter more regular contact with the health care system. Therefore, as populations age, modification of lifestyles and mental health conditions offers the potential for larger health gains. Given the key areas for public health interest, there is the need to establish the causal effect of health policies. But it is also key to the analysis of the mechanisms by which health behaviours and mental health conditions can be affected. Hence the focus of this research is on the extent to which such policies are affected by differential quality of treatment provided by primary care practices and by different socioeconomic factors of the population.
The applicant will undertake the research programme with the sponsorship of Matt Sutton in the new Centre for Health Economics and James Banks in the School of Social Sciences at the University of Manchester. The applicant will also collaborate with John Gathergood at the University of Nottingham. An overseas research visit will be held at the Department of Population Health Sciences at the University of Wisconsin in collaboration with John Mullahy. This visit will provide further training on Health Econometrics. Finally, the applicant will benefit from the multidisciplinary research environment at the new Institute of Population Health and School of Social Sciences, and from training at the Cathie Marsh Centre for Census and Survey Research at the University of Manchester and other British and European Institutions where training and conferences participation will be undertaken.
This research will make use of the English Longitudinal Study of Ageing (ELSA) - a representative survey of the population aged 50 or over and living in private households in England. ELSA contains information on a range of socioeconomic factors, cognitive abilities, health behaviours and mental health conditions. This data will be linked to administrative data on primary care practices and on house prices in England. The methods used will include policy evaluation techniques in a framework where the same individuals are tracked over time.

The aim of this Fellowship is to determine the causal and heterogeneous effects of the Quality and Outcomes Framework (QOF), on individual health behaviours and mental health conditions. The QOF was introduced in 2004 and offered financial rewards to practices for achievements of clinical indicators in specific incentivised conditions.
The objectives are to answer the following research questions:
- Are variations in health behaviours determined by heterogeneity in the treatment quality provided by primary care practices and/or by individual heterogeneity in cognitive abilities?
- Is the effect of debt problems on mental health influenced by the quality of mental health care offered by primary care practices?
The methodology is a novel application of the Continuous Treatment Approach to a longitudinal setting (Hirano and Imbens, 2004). I will exploit the introduction of the policy and differential levels of achievement rates to examine their effect on health behaviours and mental health conditions. I will analyse clusters of health behaviours to determine policy spillovers onto unincentivised behaviours. Variations in practice-level achievements and individual-level characteristics (proxied by their cognitive abilities and debt problems) will allow me to determine how such effects can be attributed to heterogeneity of the quality provided by practices and/or to heterogeneity across the treated individuals.
This analysis will be possible with the usage of newly created linkages between the English Longitudinal Study of Ageing, primary care practices and measures of house price shocks.
The scientific scope of the study includes: a) the novel application of the Continuous Treatment Approach to longitudinal data for determining the heterogeneous effect of policies and b) the exploitation of new data linkages.
The medical opportunity of the study involves the study of how clusters of health behaviours are related to different health care interventions.

The economic and societal impact of this project is of four types. First, it can enhance understanding of the effects of health interventions on clusters of individual behaviours and how they might be affected by heterogeneity of treatment quality and of socioeconomic characteristics. The focus on clusters of health behaviours and interventions is important because a specific intervention might have spillover effects on several other behaviours. For instance, smoking cessation advice might affect other lifestyle behaviours as well. This is not however a fully explored research impact especially given the financial constraints of the health sector. Second, through a better understanding of the mechanisms through which policies affect health behaviours, this Fellowship can also influence them. As health behaviours are important risk factors for chronic conditions, understanding how such policies depend on the quality of treatment provided and on the socioeconomic characteristics of the population can help prevention and management of long-term conditions. Third, the Fellowship can contribute to increase public awareness on modifiable risk factors such as lifestyles. Finally, this Fellowship can support capacity building directly through technical and policy-oriented skill development of the applicant, and indirectly through interdisciplinary networking on the topic of health interventions, mental health conditions and health behaviour.
Non-academic users and the potential benefit they can obtain from this research can be listed as follows.
i) Public sector: at national level there is the Department of Health (DH) and at the local level there are councils. The evaluation of specific policies using a representative sample of the English older population may inform the public sector on their effectiveness at the national level. In addition, the focus on treatment heterogeneity in terms of differential quality of care, and individual heterogeneity in terms of socioeconomic characteristics can aid national policy-makers understanding health inequalities. It will also benefit local policy-makers to address specific clinical and economic conditions within their local communities. Indeed, the new DH report on Public Health Responsibility Deal (2011) highlights the need to focus on the local social context of health behaviours rather than a single health issue. The importance the DH places on heterogeneity of the social context is also shown by the work commissioned from Marmot at the Institute of Health Equity to help local authorities understand how the wider social determinants of health directly affect health, and how they work indirectly to influence people's health behaviour and their ability to maintain changes in their behaviour (see Fair Society, Healthy Lives, 2010).
ii) Third sector: Age UK's aim is to improve later life for everyone through information and advice, campaigns, products, training and research. All the three projects focusing on older people's health behaviours and mental health can indeed inform Age UK's research and information campaigns.
iii) Research Institutions focused on policy issues: such as the Manchester Interdisciplinary Collaboration for Research on Ageing, the Institute for Fiscal Studies and the Centre for Market and Public Organisation. This Fellowship can help building interdisciplinary networking as well as contribute to the understanding and research of this topic by policy-oriented researchers. It can also make new data linkages known and available for evidence based policy research.
iv) Wider Public: This research can also contribute to increase public awareness on the importance of health behaviours as risk factors for cardiovascular conditions and on the relation between debt and mental health conditions.
The "Pathways to Impact" document will provide details on the timescale and activities to reach the above-mentioned non-academic users of my research.