Naturalistic observation obviously cannot be used to study all issues or phenomena. The approach is most useful when investigating complex social settings both to understand the settings and to develop theories based on the observations. It is less useful for studying well-defined hypotheses under precisely specified conditions or phenomena that are not directly observable by a researcher in a natural setting (e.g., color perception, mood, response time on a cognitive task).
Field research is also very difficult to do. Unlike a typical laboratory experiment, field research data collection cannot always be scheduled at a convenient time and place. In fact, field research can be extremely time-consuming, often placing the researcher in an unfamiliar setting for extended periods. In the Graham et al. (2006) investigation of aggression in bars, observers spent over 1,300 nights in 118 different bars (74 male–female pairs of observers were required to accomplish this feat).
Also, in more carefully controlled settings such as laboratory research, the procedures are well defined and the same for each participant, and the data analysis is planned in advance. In naturalistic observation research, however, there is an ever-changing pattern of events, some important and some unimportant; the researcher must record them all and remain flexible in order to adjust to them as research progresses. Finally, the process of analysis that follows the completion of the research is not simple (imagine the task of sorting through the field notes of every incident of aggression that occurred on over 1,300 nights). The researcher must repeatedly sort through the data to develop hypotheses to explain the data and then make sure all data are consistent with the hypotheses. Although naturalistic observation research is a difficult and challenging scientific procedure, it yields invaluable knowledge when done well.