An SLA is defined as a documented agreement between a service provider and a customer that identifies both services required and the expected level of service.
SLAs are used to measure the performance of services from the customer's point of view, and it is important that they are agreed in the wider business context.
Some of the key requirements for successful SLAs include:
* They must be related to a defined 'service' in the service catalogue. Individual metrics without a specified service context are unhelpful.
* They should relate to defined outcomes and not simply operational metrics. This can be achieved with balanced bundles of metrics, such as customer satisfaction and key business outcomes.
* They should reflect an 'agreement': an engagement and discussion between the service provider and the service consumer. It is important to involve all stakeholders, including partners, sponsors, users, and customers.
* They must be simply written and easy to understand and use for all parties.
https://www.bmc.com/blogs/itil-service-level-management/#:~:text=Service%20Level%20Agreements%20(SLA

The purpose of the continual improvement practice is to align the organization's practices and services with changing business needs through the ongoing identification and improvement of services, service components, practices, or any element involved in the efficient and effective management of products and services1. This practice needs the right culture to be embedded across the entire organization, as it requires a shared vision, commitment, empowerment, collaboration, learning, and measurement2. References: ITIL Foundation - ITIL
4 Edition, page 15; ITIL 4 - A Pocket Guide, page 34; ITIL 4 Practice Guide: Continual Improvement, page 7.