These sources of information for user research provide information over an extended period time. These approaches allow the researcher to see how user needs and experiences develop or change over time. Kuniavsky refers to these approaches as "ongoing relationships" and presents them in chapter 12.
Diaries are user-prepared reports that are submitted over an extended period, ranging from weeks to years. Kuniavsky discusses several types:
Note that even the so-called structured diaries need to provide the user some structure, usually listing possible ideas that the user should report.
Formally analyzing diaries requires coding the responses, which can then be quantitatively summarized.
These are appointed people that serve for an extended period of time and provide guidance on user needs. Qualifications include (see Kuniavsky p. 387):
These could be email messages from customers reporting problems or logs created by customer support staff. Analyzing these logs is a longitudinal source, but Kuniavsky covers this method in chapter 13.