What is the difference between the device, the phone number and the user account?¶

They are separate attribution layers: the device is physical hardware, the phone number identifies a service route, and a user account identifies access to a particular digital service.

The relationships can change¶

A handset has hardware identifiers, storage and local activity. A telephone number is delivered through a mobile subscription, SIM or eSIM and can move between devices and providers. An Apple, Google, messaging, email or other account can be signed in on several devices.

One handset may use several numbers or accounts; one number can move between handsets; one account may be shared. The three may converge at a particular time without becoming interchangeable.

Build attribution across the layers¶

A network record linked to a number may describe a subscription and connection, not the current holder. An app event identifies an account, not necessarily a handset or human operator. A device artefact may show that an account was present locally without proving who performed an action.

Use device and SIM identifiers, account registration, login history, possession, recovery details, payment, location, communications and witnesses to establish the time-specific links. Handsets, SIMs, eSIMs and subscriptions further separate the mobile-network components.