Agreed with Adam, however I'd like to add in my metaphysical experience that sometimes the tool makes the job, in that depending on what tool (or lack of tools) you are using to communicate with spirits, you'll get different levels of clarity in your answer.
For the people that aren't metaphysically experienced, in that they don't practice magic or a similar discipline or field, I'd say a spirit box would be the way to go. For those that are, if evocation doesn't fit the bill/you aren't good at it, I would recommend asking the spirit (usually aloud) to speak to you, either by tarot cards or pendulum or another form of divination. From there, you interpret the message.