“…For example, in a rigorous analysis of six European VAs, De Clercq and Bracke (2005) find that good overall performance is significantly correlated with -readiness to use severe alternative instruments.‖ Third, VAs have more effect when they require clear, specific commitments, including well-defined performance baselines and targets, timetables, monitoring, and enforcement mechanisms (EEA 1997;De Clercq and Bracke 2005;Hanks 2002). 6 4 For reviews, see Morgenstern and Pizer (2007), Croci (2005), OECD (2003), ten Brink (2002), and EEA (1997).…”