2. The influence of legislation on the availability of NPS

The most common way tackling the appearance of NPS has been legislative change. To date, we know little about the effects of blanket NPS bans in particular jurisdictions.

We observed offers and sales of NPS on Darknet markets between Sep/2016 and Aug/2019 using scraped data on 8 occasions from 20 marketplaces resulting in over 1 million listings from 19.5K vendors. We compared available listings and actual sales before and after legislative changes, implemented in Poland (Sep 2017) and Belgium (Nov 2018).

In Poland, listings for NPS products reduced substantially from 80 three months before to nil one month after legislation, but increased beyond baseline to 246 after 12 months. Revenue generated from NPS followed a similar pattern, from $1,686 monthly to nil to $1855 12 months after legislation. In Belgium, there were relatively few NPS listings three months before the change in legislation (10), but this increased one month after to 49, and disappeared entirely 12 months later. Revenue in Belgium followed a similar pattern.

Sales of NPS on Darknet markets in Poland and Belgium were not substantial even before the legislative change, although reduced sales in Poland after the change were not sustained after one year. The reverse pattern in Belgium is more difficult to explain, although must be understood in the context of relatively little NPS selling in Belgium compared to Poland. We look to contextual explanatory factors in these jurisdictions at the time of data collection.