Picking the ideal research method is contingent upon what phase or timeline the project is at:

• Strategize: Beginning phase where a great variety of ideas and opportunities can be entertained; this phase can be both quantitative or qualitative in approach (diary studies, surveys, etc.)

• Execute: At this point, a decision has been made to go into a specific design direction. This stage is also used to improve design and decreas risk. This stage is usually qualitative (field study, card sorting, etc.)

• Assess: Users are starting to engage with the product at this phase, so you can measure how well you're doing and compare with past data or against competitors. This step is quantitative (surveys, A/B testing, etc.)