What is contextual inquiry and when would you use it over a standard user interview?

Contextual inquiry is an observational research method where the researcher watches a user perform their actual work in their real environment, asking clarifying questions as they go. It is based on the master-apprentice model — the researcher is the apprentice learning from the expert user. Use it over a standard interview when:

1. Users struggle to articulate what they actually do (the "say vs do" gap).
2. You suspect the stated workflow differs from the real one.
3. You need to discover workarounds, shadow tools, and undocumented processes.
4. The task is procedural and context-dependent (e.g., how a Service Agent resolves a Case while also using Outlook and a spreadsheet). Standard interviews are faster and suitable when you need to understand attitudes, priorities, or historical context rather than observing live behaviour.