Dataset	Reporting level	Year range	Type of variable(s) derived	Details of variable
QOF	GP practice	2006/2007 to 2015/2016	Dependent	Overall QOF achievement on clinical domain. Used to generate variables of the achievement of different QOF clinical indicators
			Control	Practice-list size, percent of practice patients ≥65 years
GPPS (unweighted)a	GP practice	2008/2009 to 2015/2016	Dependent	Practice-level responses to each question in the survey Used to generate variables to investigate: patient-centred care, access to care, continuity of care, and the doctor–patient relationship
Dementia assessments data	GP practice	2013/2014 to 2015/2016	Policy	Used to identify participation in Directed Enhanced Services (DES18): Facilitating Timely Diagnosis and Support for People with Dementia
List of participation for DIS	GP practice	2013/2014 to 2015/2016	Policy	Used to identify participation in DIS
Dementia Assessment and Referral data collection	GP practice	2013/2014 to 2015/2016	Control	Used to construct ‘hospital effort’ indicator
HES	Patient	2013/2014 to 2015/2016	Control	Used to construct ‘hospital effort’ indicator
GMSb	GP practice	2011/2012 to 2015/2016	Control	Proportion of practice patients in different age and sex bands (≥65 years) used to derive expected dementia registers. GMS contract status
ADS	GP practice	2006/2007 to 2015/2016	Control	Numbers of practice patients in each LSOA. Used to generate practice- level weighted averages of rurality and deprivation
ONS: urban	LSOA	2004 to 2011	Control	Source of urban classifications. Combined with ADS to derive practice rurality measure. The 2004 data were used for missing values in 2011
ONS: deprivation	LSOA	2010 to 2015	Control	Source of IMD classifications. Combined with ADS to derive practice deprivation measure. The 2010 data were used for missing values in 2015
CCG code	GP practice	2006/2007 to 2015/2016	Control	Practice CCG code

^aGPPS is a questionnaire that is sent to a sample of each practice of England’s registered patients and is designed to collect data on different aspects of patient experience.³²

^bMethod of GMS data collection changed 2015–2016 and data are missing for around 15% of practices. ADS = Attribution Dataset. CCG = clinical commissioning group. DIS = Dementia Identification Scheme. GMS = General and Personal Medical Services dataset. GPPS = GP Patient Survey. HES = Hospital Episode Statistics. IMD = Index of Multiple Deprivation. LSOA = lower-layer super output area. ONS = Office for National Statistics. QOF = Quality and Outcomes Framework.