What indicators do police officers use to detect intoxication? A survey of Australian police

Police officers must frequently decide whether an individual has consumed alcohol or cannabis. This survey of 128 Australian Federal Police officers investigated the indicators officers use to determine whether someone is intoxicated by alcohol or cannabis, the validity of these indicators, and the factors (experience, gender, training, and confidence) that predict indicator validity. For both alcohol and cannabis, officers listed up to three visual and three verbal cues they would use to determine whether someone was intoxicated by the substance. They also provided information about their work history, demographics, training, and confidence in intoxication detection. Overall, 538 alcohol and 338 cannabis indicators were reported. Greater work experience was associated with decreased validity of cannabis indicators. Officers reported more indicators for alcohol than cannabis, but these were no more valid. The findings provide insight into what officers use to make judgments about intoxication, creating opportunities to inform police training and practices.