Every epoch of the recording is labeled as either ‘scoreable’ or ‘non-scoreable’ by our algorithm. An epoch is scoreable if the signal quality is sufficient enough for a human to score it unequivocally. The Record Quality metric is the proportion of epochs of the recording that are scoreable, therefore this metric is a high level indicator of the quality of the recording.
How it's calculated
Five independent scorers multi-scored for sleep stages 50 Dreem nights. Our deep learning model was trained on this database to labels epochs by giving them a score between 0 and 1 (0 means not scorable at all; 1 means the algorithm is 100% confident the epoch can be scored). The Dreem scorability is the percentage of the record’s epoch with a score > 0.5.
We usually consider recordings with 85% or higher quality to be acceptable as good quality recordings. For records between 70% and 85%, an expert eye can help decide whether the recording is good or not. There can be many reasons for a drop in record quality (small movements, atypical sleep, snoring).