When researching a problem, use at least two data gathering methods. For example, you
might interview people along with conducting a written survey. Or, you may hold focus
groups in addition to a telephone survey.
So what?
Every method of gathering information has some sort of blindspot. Using multiple
methods gives you a deeper insight in to the issues at hand. For example, a survey might
reveal that employees are dissatisfied, but probing in an interview might uncover their
specific concerns.