In terms of landfill diversion, considering that the dataset presents some zero values
(five of the 103 provinces observed in 1999–2006 have no MSW landfill sites and
others, e.g. Milan, closed their landfill sites, which resulted in zero values after a
certain year), we use a log linear model specification.
As far as the estimation procedure, it should be noted that we search for the
simplest specification by means of a ‘general from particular’ strategy (see note 11)
and we then test waste management and policy covariates parsimoniously to mitigate
collinearity.