DETERMINING CORRELATIONS BETWEEN TYPES OF USER IDENTIFYING INFORMATION MAINTAINED BY AN ONLINE SYSTEM

An online system maintains an identity graph having links between different types of user identifying information (e.g., email addresses, phone numbers, user identifiers) describing various users of the online system. Based on information received from various sources describing relationships between different types of user identifying information describing a user, the online system generates confidence values for each link between different types of user identifying information. In some embodiments, a confidence value accounts for an amount of time since information describing a relationship between different types of user identifying information was received from a source. If the confidence value of a link between different types of user identifying information equals or exceeds a threshold value, the online system determines the different types of user identifying information are correlated with each other, allowing the online system to correlate user identifying information without storing user identifying information received from sources.