The “simple” answer is it all depends on who you want to influence, what you want to change, and by how much. It may also depend on how optimistic or lucky you are. But the best answer is that it is surprisingly difficult to be certain one way or the other.

Journal papers have several audiences: other scientists, clinicians, policy makers, the media, and the public. In the case of injury prevention, program persons should also be on this list. These are not mutually exclusive: one may influence another. For example, if the press are interested in a publication, this may help persuade program directors or policy makers to follow the authors’ recommendations and make changes. This is especially likely if media reports stimulate widespread interest.

The most direct targets of a scientific paper, however, are other scientists. It is they who read journals the most and who quote one another’s work. Good science usually builds on the findings of others, although in my experience this logical sequence does not happen as often as it should. Nevertheless, as a rule most authors do cite pertinent work of colleagues. Accordingly, these citation counts may be one reasonable indicator that a fellow researcher’s thinking about a problem has changed. And, nowadays it is relatively easy to count the number of …