How to combine multiple research methods: practical triangulation
Patrick Kennedy has written an article on using triangulation in user research projects. To quote:
This is where the concept of “triangulation” comes into its own. Also known as “mixed method” research, triangulation is the act of combining several research methods to study one thing. They overlap each other somewhat, being complimentary at times, contrary at others. This has the effect of balancing each method out and giving a richer and hopefully truer account.