Résultat de la recherche
A step-by-step procedure to implement discrete choice experiments in Qualtrics
Discrete choice experiment (DCE) is a well-established technique to elicit stated preferences. It is frequently used in social sciences, where revealed preferences are difficult or sometimes even impossible to collect. A DCE consists in a series of choice tasks, in which survey respondents are requested to select the alternative they prefer among a few ones. Even though DCEs are conceptually well-known and documented, the practitioner may face technical issues once turning to their concrete implementation. This methodological note provides a step-by-step procedure to implement a DCE using the survey software Qualtrics. The procedure is largely automated, relying on the statistical software Stata and using HTML code to display the choice tasks in a pleasant way. Basic knowledge of Stata and HTML is desirable but not an absolute requirement. This note is intended to Qualtrics users, and prior knowledge of this survey tool is therefore assumed. A full working example with all codes and material is provided and presented.
Testing for Granger causality in panel data
With the development of large and long panel databases, the theory surrounding panel causality evolves quickly, and empirical researchers might find it difficult to run the most recent techniques developed in the literature. In this article, we present the community-contributed command xtgcause, which implements a procedure proposed by Dumitrescu and Hurlin (2012, Economic Modelling 29: 1450–1460) for detecting Granger causality in panel datasets. Thus, it constitutes an effort to help practitioners understand and apply the test. xtgcause offers the possibility of selecting the number of lags to include in the model by minimizing the Akaike information criterion, Bayesian information criterion, or Hannan–Quinn information criterion, and it offers the possibility to implement a bootstrap procedure to compute p-values and critical values.
A simple command to calculate travel distance and travel time
Obtaining the routing distance between two addresses should not be a hassle with current technology. Unfortunately, this is more complicated than it first seems. Recently, several commands have been implemented for this purpose (traveltime, traveltime3, mqtime, osrmtime), but most of them became obsolete only a few months after their introduction or appear complicated to use. In this article, we introduce the community-contributed command georoute, which retrieves travel distance and travel time between two points defined either by their addresses or by their geographical coordinates. Compared with other existing commands, it is simple to use, efficient in terms of computational speed, and versatile regarding the information that can be provided as input.