In this paper we detail the entire Regression Discontinuity Design (RDD) history, including its origins in the 1960s, and its two main waves of formalization in the 1970s and 2000s, both of which are rarely acknowledged in the literature. Also, we dissect the empirical work into fuzzy and sharp designs and provide some intuition as to why some rule‐based criteria produce imperfect compliance. Finally, we break the literature down by economic field, highlighting the main outcomes, treatments, and running variables. Overall, we see some topics in economics gaining importance through time, like the cases of health, finance, crime, environment, and political economy. In particular, we highlight applications in finance as the most novel. Nonetheless, we recognize that the field of education stands out as the uncontested RDD champion through time, with the greatest number of empirical applications.

In this paper we detail the entire Regression Discontinuity Design (RDD) history, including its origins in the 1960's, and its two main waves of formalization in the 1970's and 2000's, both of which are rarely acknowledged in the literature. Also, we dissect the empirical work into fuzzy and sharp designs and provide some intuition as to why some rule-based criteria produce imperfect compliance. Finally, we break the literature down by economic field, highlighting the main outcomes, treatments, and running variables employed. Overall, we see some topics in economics gaining importance through time, like the cases of: health, finance, crime, environment, and political economy. In particular, we highlight applications in finance as the most novel. Nonetheless, we recognize that the field of education stands out as the uncontested RDD champion through time, with the greatest number of empirical applications.

We revisit an old question but with a new identification strategy, namely the difference in exchange rate effects between announced (“vocal”) and secret (“dirty”) foreign exchange intervention. Using a Regression Discontinuity Design, we exploit a rule-based intervention mechanism enacted by the Central Bank of Colombia that, under observable and deterministic conditions, triggered either the issuance of FX options or the ability to exercise them. We take the former (issuance) as central bank announcements under a sharp setting, since the rule and information that triggered the issuance of options was public, and we take the latter (exercise) as secret trades under a fuzzy setting, since traders could have chosen (but were not required) to exercise their options in the following days after issuance. Our results indicate that, unconditionally, both announcements and secret trades carry similar effects. However, the effects of announcements are considerably amplified conditional on: (i) higher central bank credibility, (ii) less frequent announcements, and (iii) episodes of higher FX volatility.