Evaluating Public Policies with High Frequency Data: Evidence for Driving Restrictions in Mexico City Revisited

The evaluation of public policies is on the heart of the e cient management of public resources. As complex as it generally is, any reform should be assessed on its ability to achieve its preconceived goals. This research paper attempts to show the importance of the design of a public policy's empirical evaluation, considering the susceptibility that its conclusions might have to changes in the approach to the data. The work of Davis (2008), which nds that a driving restrictions program had no impact on air quality in Mexico City, is revisited showing that reasonable changes in the methodology used can dramatically alter its conclusions. Additionally, evidence is presented that shows the success of the restrictions program in reducing air pollution by 12 to 18% during the first months of its implementation followed by a gradual increase in pollutants concentration, consistent with more limited opportunities for adaptation to the policy in the short-run. Finally, an alternative and robust framework is proposed to carry out the policy evaluation con rming the reduction of pollution right after the program's implementation.Policy evaluation, air quality, regression discontinuity

The Effect of Transport Policies on Car Use: Theory and Evidence from Latin American Cities

In an effort to reduce air pollution and congestion, Latin American cities have experimented with different policies to persuade drivers to give up their cars in favor of public transport. Two notable examples are the driving restriction program introduced in Mexico-City in November of 1989 –Hoy-No-Circula (HNC)– and the public transport reform carried out in Santiago in February of 2007 –Transantiago (TS). We develop a simple model of car use and ownership, and show that policies that may appear effective in the short run can be highly detrimental in the long run, i.e., after households have adjusted their stock of vehicles. Based on hourly concentration records of carbon monoxide, which comes primarily from vehicles exhaust, we find that household’s responses to both HNC and TS have been remarkably similar and consistent with the above: an expected short-run response followed by a rapid (before 11 months) increase in the stock of vehicles.Public transport, driving restrictions, car use, air pollution, transport policies

Reappraisal generation after acquired brain damage:the role of laterality and cognitive control

In the past decade, there has been growing interest in the neuroanatomical and neuropsychological bases of reappraisal. Findings suggest that reappraisal activates a set of areas in the left hemisphere (LH), which are commonly associated with language abilities and verbally mediated cognitive control. The main goal of this study was to investigate whether individuals with focal damage to the LH (n = 8) were more markedly impaired on a reappraisal generation task than individuals with right hemisphere lesions (RH, n = 8), and healthy controls (HC, n = 14). The reappraisal generation task consisted of a set of ten pictures from the IAPS, depicting negative events of different sorts. Participants were asked to quickly generate as many positive reinterpretations as possible for each picture. Two scores were derived from this task, namely difficulty and productivity. A second goal of this study was to explore which cognitive control processes were associated with performance on the reappraisal task. For this purpose, participants were assessed on several measures of cognitive control. Findings indicated that reappraisal difficulty � defined as the time taken to generate a first reappraisal � did not differ between LH and RH groups. However, differences were found between patients with brain injury (LH + RH) and HC, suggesting that brain damage in either hemisphere influences reappraisal difficulty. No differences in reappraisal productivity were found across groups, suggesting that neurological groups and HC are equally productive when time constraints are not considered. Finally, only two cognitive control processes inhibition and verbal fluency- were inversely associated with reappraisal difficulty. Implications for the neuroanatomical and neuropsychological bases of reappraisal generation are discussed, and implications for neuro-rehabilitation are considered