Advantages

- All the advantages of the simple single-room setup also apply to this setup.
- Observers get to view the test as much as they like without having to worry about interfering. They are free to come and go as they please without distracting anyone. This is especially crucial for very lengthy tests, where observers may be interested only in certain portions or cer tain types of participants. More important, they are able to talk among themselves, discussing test observations.