A computing arrangement receives data. The data is from computer apps running on computer devices. The data has user identity data and associated device identity data. A memory stores sets of identity data. A respective set of identity data is associated with a user identity. Sets of identity data comprise at least one user identity data, at least one device entity data and information defining a connection relationship between the identity data of the respective set of identity data. At least one processor determines in response to received user identity data and device identity data that a first stored set of identity data is to be divided into two or more sets of user identity data. At least two sets of user identity data are associated with different user identities. The set of identity data is divided in dependence on the information defining the connection relationships.