# Contact quality gates (CQ Gates)
Contact quality and EEG quality from an EMOTIV headset is detected using EMOTIV's algorithms.
When building an experiment, you can add contact quality gates at the beginning of each phase. When contact quality gates are enabled, if contact quality drops during a phase (below 100%), the participant will be prompted to adjust their headset before continuing to the next phase.
#### What is contact quality?
Contact quality indicates the resistance between each sensor on a headset and a participant’s scalp. It does not directly measure the connection of the reference sensors.
#### What is EEG quality?
Emotiv has developed a machine learning algorithm that assesses whether the EEG signals recorded are brain waves or noise. EEG quality is the best way to see if a headset is adjusted correctly and that the sensors have a good connection with a participant’s scalp.
At the beginning of an experiment, the participant will be asked to adjust their headset (if needed) so its sensors achieve 100% EEG quality. When more than 80% EEG quality is achieved, all the sensors will be green in Emotiv Launcher and the participant can proceed with the experiment.
####
#### How do I add contact quality gates to my experiment?
To add contact quality gates to an experiment, click on the **CQ Gate** button at the top of the editing screen. Then, select the phase(s) you want to apply contact quality gates to.
