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Researchers planning a clinical trial should have a clear research question that they wish to investigate and which they will seek to answer in their study. The task of defining a research question lays the foundation for the work that will be done in the trial and will determine the methodology to use, data to collect, analyses to perform and conclusions to draw.

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In the Smiley Faces task, participants are simply asked to draw a smiley face and to write their name, gender and age, and the event at which the drawings were collected next to the drawing if they wish. No clear research question is presented in advance and, at the outset, they are not aware of the reasons for the task. This deliberate lack of an a priori research question is used to illustrate how the absence of a clear research question means that neither the researcher nor the study participants know how their data will be used, and how this lack of clarity generates doubt about which baseline and follow-up data are most important. After the faces have been drawn, the participants are asked to suggest possible research questions, which usually leads to a variety of ideas, some of which cannot be addressed fully by the collected data which is solely the drawings of the faces and the limited amount of information added to them by the participants. This illustrates how good trial conduct should ensure that the research question and the relevant data are clear in advance and communicated effectively to potential participants. The Smiley Faces task illustrates the dangers of formulating research questions after the data have been gathered, which leaves the way open for data-dependent biases, multiplicity, wasteful collection of data that will not be used, failure to collect the data that are most important and an inappropriate estimate of the sample size for the trial.