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You wish to be useful to them . Much of what is written about users ' needs for information is speculative that is , the author speculates about what would or would not be useful to users , not testing the speculative ideas with empirical data or with direct observations or otherwise working with users . The kind of skills that we observe them acquiring during our experiment will later be useful to them in the same way as something that they would learn from a book or a lecture . When using such a procedure , it can be useful to explain it beforehand , when describing the kinds of questions one is proposing to ask .