Vollaard, B.

container treatment partijen effect garbage cleaning location litter littering worden control number treatment area control area treatment effect service experiment household items level percent gemeente project period appointment household people build-up afternoon result morning behavior table cleaning services environment publieke samenwerking field experiment overheid kunnen risico littering behavior resident observation frequency gedrag field figure column month verschillende checklist container locations coefficient andere contribution heeft betrokken partij evidence planvorming belang intervention study doelen analysis rapport estimate estimation university tussen equation 1 percent level belangen 5 percent level minimumvariant 10 percent level welke telephone appointments service workers garbage containers