Final answer:
Observation research has drawbacks including setup and control difficulties, observer bias, and being time-consuming, yet offers high ecological validity.
Step-by-step explanation:
The biggest drawbacks of observation research include its difficulty to set up and control, the potential for observer bias, and the time-consuming nature of the method. A lack of control over the research environment can result in missed opportunities to observe the target behavior, as the subject may not perform the behavior when the researcher is watching. To mitigate bias, clear criteria for recording behaviors and inter-rater reliability tests are essential. Despite these drawbacks, observation research is valuable for its high degree of ecological validity, providing accurate information by observing individuals or groups in their natural settings. However, the validity of the data can sometimes be compromised if subjects are aware they are being observed.