{'fraction_non_alphanumeric': 0.029468599033816423, 'fraction_numerical': 0.01497584541062802, 'mean_word_length': 5.2192192192192195, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Examining new-generation transdermal alcohol biosensor performance across laboratory and field contexts.

BACKGROUND
Wrist-worn transdermal alcohol sensors have the potential to change how alcohol consumption is measured. However, hardware and data analytic challenges associated with transdermal sensor data have kept these devices from widespread use. Given recent technological and analytic advances, this study provides an updated account of the performance of a new generation wrist-worn transdermal sensor in both laboratory and field settings.


METHODS
This work leverages machine learning models to convert transdermal alcohol concentration (TAC) data into estimates of Breath Alcohol Concentration (BrAC) in a large-scale laboratory (N=256, study 1) and pilot field sample (N=27, study 2). Specifically, in both studies, the accuracy of this translation is evaluated by comparing BAC estimates yielded from BACtrack Skyn to real-time breathalyzer measurements collected in the lab and in the field.


RESULTS
The newest version of the Skyn device demonstrates a substantially lower error rate compared to older hand-assembled prototypes (0%-7% vs 29%-53%). On average, real-time estimates of BrAC yielded from these transdermal sensors are within 0.007 of true BAC readings in the laboratory context and within 0.019 of true BrAC readings in the field. In both contexts, distance between true and estimated BrAC was larger when only alcohol episodes were examined (0.017 lab; 0.041 field). Lastly, results of power-law-curve projections indicate the accuracy of transdermal BrAC estimates in real-world contexts has the potential to improve markedly (>25%) given adequately sized datasets for model training.


CONCLUSION
Findings from this study indicate the latest version of transdermal wrist sensor holds promise for the assessment of alcohol consumption in field contexts. A great deal of additional work is left to be done before we have a full picture of the utility of these devices, including research with large participant samples in field contexts.