For better or worse, policymakers have different incentives than academics. The upside is that a public agency does not need to chase refereed publications, so the non-results (instances of interventions that "didn't work" / didn't change behavior) won't necessarily end up gathering dust in the drawer.
But it is very hard to put in place incentives to report all results. The existence of your unit is (superficially) more justifiable if you show that your experiments "worked".
For now, it is exciting to see that many people across a wide variety of countries and agencies are able to test their ideas.
Policy testing and experiments, often involving some application of behavioral economics, are clearly catching on. If the trend (text message reminders, local lotteries, innovative information presentation approaches, etc.) continues, it would be helpful to keep track of the initiatives and get some sense of earlier success rates. I will try to keep track of the more comprehensive reports - these four pieces look like the main references for now:
European Commission: Behavioural insights applied to policy: European Report 2016 - Overview across 32 European countries (by Joana Sousa Lourenço, Emanuele Ciriolo, Sara Rafael Almeida, and Xavier Troussard)
World Bank: World Development Report 2015: Mind, Society, and Behavior
OECD: Regulatory Policy and Behavioural Economics
Short summaries are available for other countries as well:
- Czech Republic
- The Netherlands