What characteristic of the EEG should be evaluated to ensure accurate recordings in a clinical setting?

The common mode rejection ratio (CMRR) is fundamental in ensuring accurate EEG recordings, as it measures the ability of the EEG system to reject common noise or interference that can corrupt the data being collected. A high CMRR indicates that the equipment can effectively differentiate between actual brain activity signals and extraneous electrical noise, which might come from environmental factors or the patient's own physiological signals. This is crucial as it directly impacts the fidelity and clarity of the EEG results, allowing for more accurate interpretation and diagnosis.

While parameters like the electrode cap size, the technician's experience, and the patient's age can influence the overall setup and outcomes of an EEG, they do not directly relate to the system's ability to reject noise or ensure high-quality data collection in the way that CMRR does. Ensuring that the EEG equipment has a suitable CMRR is essential for obtaining reliable and precise recordings, which is why it is a key characteristic to evaluate in a clinical setting.