01 See, for example, Beyer, H., & Holtzblatt, K. (1997). Contextual Design: Defining Customer-Centered Systems. Elsevier.
Contextual interviews can be done, for example, with employees at their workplace or with customers during a specific moment of their customer experience. Contextual interviews are used to understand a certain group of people better: to understand their needs, emotions, expectations, and environment (useful for personas), but also to reveal formal and informal networks and hidden agendas of specific actors (useful for system maps). Besides, such interviews help to understand particular experiences as interviewees can demonstrate actions in detail and in context (useful for journey maps). Try to ask your interviewees about a specific experience that they’ve had (e.g., the last time they used the service) and to demonstrate details of this concrete experience. It is often easier for people to articulate pains and gains when they refer to concrete examples than when describing an experience in more general terms. Contextual interviews can be conducted rather openly, following one leading research question, or in a semi-structured way, following interview and observation guidelines (see participant observation). 
In contrast to retrospective interviews, contextual ones are conducted in situ, with the advantage that researchers can observe the environment and interviewees can point to elements in the environment. This makes an interview much more tangible and active. Interviewees tend to be more open and engaged, as they are often conducted in a context that is familiar to the interviewee. Interviewees also tend to remember more specific details than in retrospective interviews or focus groups, and researchers gain a much more holistic understanding. Often, contextual interviews use techniques like the Five Whys to gain a deeper understanding about the underlying motivations for specific actions of the interviewee. It’s important to document the situational context in which the interview takes place. Besides season, weekday, time, and place, other factors may affect the situational context, such as weather conditions or other customers. Also, be aware of the interviewees’ mood, and observe their gestures and body language.