The odour concentration where 50 % of the population can recognize and identify what the odour sample represents. Not to be confused with the Detection Threshold (DT), where the RT is typically higher than the DT. For example, while an assessor or panelist is involved in a presentation using the SM100 with N-butenol, their DT may be detected at hole number 4 on the plate and RT may be detected on the 7th hole. This indicates that the assessor may detect a scent on number 4, but unsure as to what it is. As the concentration amount increases, they may be able to recognize the scent and confirm that it is in fact N-butenol they smell.