Every time an individual has an interaction with an NHS organisation, information is collected about them. Health and care staff involved in your care collect this information about you for example, so that there is a record of treatments or drugs given, or so that hospital staff can share your test results with you.
The information collected about you can also be used to improve health and care services for you, your family and for other patients through research and planning. This information can be personally identifiable, de-personalised or anonymous.
Using information in this way, NHS and social care organisation can plan which services to run and where, so that the right health and care support is available in the right place and to improve diagnosis and treatment.

Population Health is about improving the health and wellbeing outcomes of an entire population or local community. By analysing anonymous health and care information and looking at trends, we can turn insights into actions to improve the health and wellbeing of people, and help reduce inequalities across a specific area.
For example It can include actions to reduce illness and disease, as well as improving other factors that influence health and wellbeing like exercise, diet, housing and social interaction, and requires working with local communities, the voluntary sector and other partner organisations.
For further information see the King's Fund report: A Vision for Population Health.