What research technique is used to develop personas?

A journey map is a research technique that is used to develop personas. A journey map is a visual representation of the steps, interactions, and emotions of a user as they go through a process or a service. A journey map can help develop personas by identifying the pain points, opportunities, and gaps in the current state, and by generating ideas for improving the user experience and value proposition in the future state. A journey map can also help communicate the user needs and expectations to the stakeholders and align them on a common vision and goal.

References:

Journey Maps - Scaled Agile Framework

Journey Mapping 101 | Nielsen Norman Group

Journey Mapping: The Ultimate Guide | Miro

Journey Mapping: How to Create One and Why It’s Important