Best to use when
Who, What, When, Where is best to use to find out what the different questions are surrounding a topic or problem. It helps uncover problems that are underlying or associated with the main problem statement. It also helps transfer the responsibility of asking the right questions for the entire sprint team.
It works really well with a large group of people to get them all on the same page quickly. It is based off the game Game Storming
Divide the whiteboard into four sections and give each a title of Who, What, When, and Where.
Start with Who. Each player should write down as many questions starting with "Who" related to the problem we want to solve. e.g. "Who spends hours manually manipulating data from one format to another?" "Who receives gifts they don't want on their birthday?"
Post all the questions under the who section of the whiteboard. Ask a few players to group similar questions.
Have Product Owner or Facilitator answer the questions, mark them later for further research or reword them as an assumption that needs testing.
Repeat for each of the remaining questions.