Table 1.

Definitions of adherence, compliance, concordance, and persistence

Term	Definition
1. Compliance	The extent to which the patient’s behavior matches the prescriber’s recommendations. There is an implied lack of patient involvement.
2. Adherence	The extent to which the patient continues the agreed-upon mode of treatment under limited supervision when faced with conflicting demands.
3. Concordance	Encompasses the process in which doctor and patient agree therapeutic decisions that incorporate their respective views, to a wider concept which stretches from prescribing communication to patient support in medicine taking.
4. Persistence	This refers to the duration of time that the patient continues a specified therapy and may or may not have conformed to the dosing schedule during that time.