The third Swiss Stata Conference took place virtually on 19 November 2020.
Proceedings
| 10:30–11:00 | randregret: A command for fitting random regret minimization models using Stata
        Abstract:
        In this presentation, we describe the randregret command, which
        implements a variety of random regret minimization (RRM) models. The
        command allows the user to apply the classic RRM model (Chorus 2010),
        the generalized RRM model (Chorus 2014), and also the mu-RRM and pure
        RRM models (Van Cranenburgh, Guevara, and Chorus 2015). 
        We illustrate
        the usage of the randregret command using stated choice data on
        route preferences. The command offers robust and cluster standard-error
        correction using analytical expressions of the score functions. It also
        offers likelihood ratio tests, which can be used to assess the relevance
        of a given model specification. Finally, predicted probabilities from
        each model can be easily computed using the randregretpred
        postestimation command.
         References: Chorus, C. G. 2010. A new model of random regret minimization. European Journal of Transport and Infrastructure Research 10(2). Chorus, C. G. 2014. A generalized random regret minimization model. Transportation Research Part B: Methodological 68: 224–238. Van Cranenburgh, S., C. A. Guevara, and C. G. Chorus. 2015. New insights on random regret minimization models. Transportation Research Part A: Policy and Practice 74: 91–109. 
 Contributors: Michel Meulders Martina Vandebroek KU Leuven 
         Additional information: Álvaro A. Gutiérrez Vargas KU Leuven | 
| 11:00–11:30 | How to assess the fit of multilevel logit models with Stata? A project in progress
        Abstract:
	Stata 16 includes the multilevel model for binary (melogit) and 
	ordinal logits (meologit). Unfortunately, except for the global Wald 
	test of the estimated fixed effects, both models do not provide any fit measure to
	assess its practical significance. Therefore, I developed an ado-file to
	calculate McFadden's and McKelvey and Zavoina's pseudo-R². It estimates the 
        intraclass correlation (ICC) of the dependent variable for the actual
        sample to assess the maximum of the contextual effect, too. Since the
        early 90s, a lot of Monte Carlo simulation studies (Hagle and Mitchell
        1992; Veall and Zimmermann 1992, 1993, 1994); Windmeijer 1995; DeMaris
        2002) proved that McKelvey and Zavoina's pseudo-R² is the best one to assess
        the fit of binary and ordinal logit models. My ado-file calculates this 
        fit measure in two complementary ways: for the fixed effects
        only and for the fixed and random effects together. The
        estimation of McFadden's pseudo-R² uses two different zero models:
        the random-intercept-only model (RIOM) knowing the contextual
        units and the fixed-intercept-only model (FIOM) ignoring the
        contextual units completely. For each of them, it calculates the global
        likelihood-ratio χ² test statistic 1 whether all fixed effects or all
        fixed and random effects are zero in the population. It performs two
        global likelihood-ratio χ² tests for all fixed effects and all fixed
        and random effects using a probability weight for each level. An
        empirical study of drug consumption in European countries demonstrates
        the usefulness of my fit_meologit_2lev.ado or fit_meologit_3lev.ado
        files for multilevel binary and ordinal logit models.
         
         
         Additional information: Wolfgang Langer Martin Luther Universität Halle-Wittenberg | 
| 11:30–12:00 | xtbreak: estimating and testing break points in panel data in Stata
        Abstract:
	I present the new community-contributed command xtbreak, which allows 
	the empirical analysis of multiple structural changes in panel data. The
	panels may be strongly cross-sectionally dependent, where
	cross-sectional dependence takes the form of a multifactor structure in
	the errors. The number of break points and their dates are treated as unknown. 
	The command includes the following two hypothesis tests. First,
        a test of the null hypothesis of no breaks against a user-specified
        number of breaks. Second, a test of the null hypothesis of k numbers of
        breaks against the alternative of k+1 number of breaks. Once the number
        of breaks has been specified, the command allows the estimation of the
        break dates and the construction of confidence intervals for these
        dates. The syntax and options of xtbreak are explained. Examples 
        for the estimation of the breakpoints and testing those are given.
         
         
         Additional information: Jan Ditzen Heriot Watt University | 
| 1:00–1:30 | acreg: Arbitrary correlation regression
        Abstract:
	In this presentation, we present acreg, a new Stata command that
	implements the standard error correction proposed in Colella et al.
	(2019). This command computes regression coefficients' standard errors,
	accounting for dependence across arbitrary correlation structures in a
	flexible way. Arbitrary here refers to the way units are correlated with 
	each other: we impose no restrictions so that our approach can be used 
        with a wide range of data. In particular, this command allows the
        estimation of OLS and 2SLS coefficient correcting standard errors across
        units in three environments: in a spatial setting using objects'
        coordinates or distance between units, in a network setting starting
        from the adjacency matrix, and in a multi-way cluster framework taking
        multiple clustering variables as input. This command suits both
        cross-sectional and panel databases. Distance and time cutoffs can be
        specified by the user and linear decay in time and space are also
        optional.
        
 Contributors: Rafael Lalive Seyhun Orcan Sakalli Mathias Thoenig Université de Lausanne 
         Additional information: Fabrizio Colella Université de Lausanne | 
| 1:30–2:00 | A new implementation of relative distribution methods in Stata
        Abstract:
	A relative distribution is defined as the distribution of the relative 
	ranks that the outcomes of one distribution take on in another
	distribution. An example is the relative positions that women's wages
	take on in the distribution of men's wages. In this presentation, I will 
	discuss a new implementation of relative distribution methods in Stata. 
	The new 
	command called reldistcan be used to estimate and plot 
        the relative density function (relative PDF), a histogram of the relative
        distribution, or the relative distribution function (relative CDF), or
        to estimate polarization indices and descriptive statistics of the
        relative data. The command also supports decomposition of the relative
        distribution by adjusting differences in location, scale, and shape or
        differences in covariate distributions (using reweighting). Standard
        errors are estimated based on influence functions and support complex 
        survey data.
         
         
         Additional information: Ben Jann Universität Bern | 
| 2:00–2:30 | Quantile and distribution regression in Stata: Algorithms, pointwise and functional inference
        Abstract:
	This presentation and the related commands offer fast estimation and 
	inference procedures for the linear quantile and distribution regression
	models. First, qrprocess and drprocess implement new algorithms 
	that are much quicker than the built-in Stata commands, especially when a
	large number of regressions or bootstrap replications must be 
	estimated. Second, the commands provide analytical estimates of the
        variance–covariance matrix of the coefficients for several regressions
        allowing for weights, clustering, and stratification. Third, in addition
        to traditional pointwise confidence intervals, these commands also
        provide functional confidence bands and tests of functional hypotheses.
        Fourth, predict—called after either qrprocess or 
        drprocess—can
        generate monotone estimates of the conditional quantile and distribution
        functions obtained by rearrangement. Fifth, plotprocess conveniently
        plots the estimated coefficients with their confidence intervals and
        uniform bands.
         
         
         Additional information: Blaise Melly Universität Bern | 
| 3:00–3:30 | arhomme: A Stata implementation of the Arrellano/Bonhomme (2017) estimator for quantile regression with selection correction
        Abstract:
	Despite constituting a major theoretical breakthrough, the quantile 
	selection model of Arrellano and Bonhomme (2017, Econometrica, Vol. 85,
	pp. 1–28) based on copulas has not found its way into many empirical
	applications. We introduce the command arhomme, which implements
	different variants of the estimator along with standard errors based on
	subsampling. We illustrate the command by replicating the empirical
	application in the original article and a related application in
	Arrellano and Bonhomme (2017, Handbook of Quantile Regression, Ch. 13). 
 Contributor: Pascal Erhardt University of Tübingen 
         Additional information: Martin Biewen University of Tübingen | 
| 3:30–4:00 | Conditional likelihood models for distributional regression analysis
        Abstract:
	This presentation illustrates the use of conditional likelihood models for
	"distributional regression" analysis.  Conditional likelihood models
	impose specific parametric functional forms for an outcome variable of
	interest—for example, normality, log-normality, Gamma distribution, 
	or more elaborate shapes—but allow the shape parameters to 
	vary with
        covariates; for example, assuming normality and allowing both the mean
        and the standard deviation to vary with a vector of explanatory
        variables. Drawing on examples from income distribution analyses, I show
        how such models are fit in Stata, relying on a range of community-contributed 
	commands, and how predictions and counterfactual simulations
        for both the conditional and the marginalized (unconditional)
        distributions can be easily obtained from the fitted models. I also
        discuss the pros and cons of such conditional likelihood models in
        comparisons with quantile regression or distribution regression
        approaches.
         
         
         Additional information: Phillippe Van Kerm Universität von Luxemburg | 
| 4:00–4:30 | Econodistplot: distribution box plots, economist-style
        Abstract:
	I present a new Stata package called conodistplot, which produces 
	simple box plots showing median and interquantile ranges defaulting to
	the 10% and 90% percentiles. These plots have been introduced by The
	Economist 
	(www.economist.com/united-states/2019/06/29/willtransparent-pricing-make-americas-health-care-cheaper) 
	and slightly adapted by Bob Rudis for the R platform (cinc.rud.is/w
eb/packages/ggeconodist). The
        package presented here reproduces the look of Rudis' graphs, with the
        motivation of creating an easily legible and visually appealing data
        summary.
         
         
         Additional information: Alex Gamma Universität Zürich | 
| 5:00–6:00 | Introduction to Bayesian Statistics Using Stata
        Abstract:
	Bayesian analysis has become a popular tool for many statistical 
	applications. Yet many data analysts have little training in the theory
	of Bayesian analysis and software used to fit Bayesian models. This presentation
	will provide an intuitive introduction to the concepts of Bayesian
	analysis and will demonstrate how to fit Bayesian models using Stata. 
	No
        prior knowledge of Bayesian analysis is necessary. Some specific topics
        I will cover are the relationship between likelihood functions, prior
        distributions, and posterior distributions; Markov chain Monte Carlo
        (MCMC) using the Metropolis—Hastings algorithm; and how to use Stata's
	bayes prefix to fit Bayesian models.
         
         
         Additional information: Gustavo Sánchez StataCorp | 
| 6:00–6:30 | Open panel discussion with Stata developers StataCorp | 
Scientific committee
| Ben Jann Universität Bern | Blaise Melly Universität Bern | 
Logistics organizer
 
      The logistics organizer for the 2020 Swiss Stata Conference is Universität Bern and Ritme, scientific solutions, the official distributor of Stata in Belgium and Switzerland.
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