The future is now-using personal cellphones to gather data on substance use and related factors

摘要

For more than a century, the vast majority of insights into personal substance use were gathered by asking participants to report their behaviour retrospectively by ticking boxes in paper-and-pencil questionnaires and, increasingly nowadays, through online data-gathering methods. Gathering data with retrospective recall is considered cost-efficient and convenient, but it largely underestimates substance use in a given population. For example, survey estimates reproduce only 30-70% of the total per capita alcohol consumption compared with sales statistics [1,2]. The fact that heavy substance users tend to be under-represented in surveys was suggested as one reason for this underestimation [1]. Another reason is that, due to memory deficits, people tend to remember only part of the amounts consumed [1,3]. Such a recall bias can be present after only a couple of days [4].