What is a disadvantage of using observation as a primary research method?

Using observation as a primary research method can introduce a disadvantage when the presence of the observer affects the behavior of those being observed. This phenomenon, often referred to as the "Hawthorne effect," occurs when individuals alter their actions in response to being watched or evaluated. Consequently, the data collected may not accurately represent true behaviors, as the participants might behave differently than they would in a normal setting.

This inherent challenge underscores the importance of being aware of the limitations of observation as a research method. Ensuring that observations are as unobtrusive as possible can help mitigate this bias, but it remains a significant consideration in the overall reliability and validity of the research findings. The other options do not reflect true disadvantages of observational research; for instance, observational methods do not guarantee unbiased results, and they are not necessarily quick or independent of factors like gender.