Modern day UX research methods answer a wide range of questions. To help you know when to use which user research method, Kelley Gordon and Christian Rohrer of the Nielsen Norman Group mapped each of 20 methods across 3 dimensions and over time within a typical product-development process:
- Attitudional vs behavioral
- Qualitative vs quantitative
- Context of product use
For further detail, see When to Use Which User-Experience Research Methods.