Understanding and teaching unequal probability of selection

This paper focuses on econometrics pedagogy. It demonstrates the importance of including probability weights in regression analysis using data from surveys that do not use simple random samples (SRS). We use concrete, numerical examples and simulation to show how to effectively teach this difficult material to a student audience. We relax the assumption of simple random sampling and show how unequal probability of selection can lead to biased, inconsistent OLS slope estimates. We then explain and apply probability weighted least squares, showing how weighting the observations by the reciprocal of the probability of inclusion in the sample improves performance. The exposition is non-mathematical and relies heavily on intuitive, visual displays to make the content accessible to students. This paper will enable professors to incorporate unequal probability of selection into their courses and allow students to use best practice techniques in analyzing data from complex surveys. The primary delivery vehicle is Microsoft Excel®. Two user-defined array functions, SAMPLE and LINESTW, are included in a prepared Excel workbook. We replicate all results in Stata® and offer a do file for easy analysis in Stata. Documented code in Excel and Stata allows users to see each step in the sampling and probability weighted least squares algorithms. All files and code are available at www.depauw.edu/learn/stata.unequal probability; complex survey; simulation; weighted regression

Why Excel?

This article is not the usual Excel pedagogy fare in that it does not provide an application or example taught via a spreadsheet. Instead, it briefly reviews the history of spreadsheets in the economics classroom and explores the current environment, with an emphasis on modern learning theory. The conclusion is not surprising: spreadsheets improve learning outcomes across the economics curriculum and are increasingly being used. They offer the “just right” option that gives a middle way between too little and too much focus on software in an economics course

A Covid-19 Teaching Example: Pooled Testing with Microsoft Excel

This paper uses pooled testing as a teaching example for undergraduate statistics, econometrics, or quantitative methods courses. It offers step-by-step instructions to create an Excel spreadsheet that uses Monte Carlo simulation to find the optimal group size for a given infection rate. A completed version of the spreadsheet, along with readings, questions, and analytical solution is available at tiny.cc/pooledtesting

Let’s Put Demography Back into Economics: Population Pyramids in Excel

The economics curriculum today does not emphasize the study of population. This needs to change immediately because we are in the midst of another demographic sea change, slamming on the brakes right after a rapid acceleration during the last half of the 20th century. Instead of glibly tossing a dependency ratio onto a slide, this paper offers an easy way to improve demographic literacy using population pyramids. Simulation is used to explain the pyramid and its dynamic properties, and then real‐world data are presented. Microsoft Excel’s ability to act as a browser and download data with a single click of a button provides a flexible, powerful tool to explore historic, current, and predicted age distributions of various countries

Visualizing Income Distribution in the United States

Background: Visit research.depauw.edu/econ/incomevis to see a novel, eye-catching visual display of the income distribution in the United States that conveys fundamental information about the evolution and current level of income inequality to a wide audience. We use IPUMS CPS data to create household income deciles adjusted for price level and household size for each of the 50 states and the District of Columbia from 1976 to 2018. We adjust for state price differences from 2008 to 2018. Plotting these data gives a 3D chart that provides a startling picture of income differences within and across states over time. Those interested in further customization can use our Python visualization toolbox, incomevis, available at pypi.org/project/incomevis

Teaching Income Inequality with Data-Driven Visualization

The distribution of household income is a central concern in economics due to its strong influence on society’s well-being and social cohesion. Yet, non-expert audiences face serious obstacles in understanding conventional measures of inequality. To effectively communicate the extent of income inequality in the United States, we have developed a novel technique for visualizing income distribution and its dispersion over time by using U.S. household income microdata from the Current Population Survey. The result is a striking dynamic animation of income distribution over time, drawing public attention, and encouraging further investigation of income inequality. Detailed implementation is available at github.com/sangttruong/incomevis. An interactive demonstration of our project is available at research.depauw.edu/econ/incomevis

Accessing IRS Form 990 Data with Excel

Form990.xlsm, freely available at archive.org/details/Form990.xlsm, is a standalone, macro-enabled Excel workbook that allows users to easily download and analyze IRS Form 990 tax data. This information is extremely difficult to access in machine-readable format, but the IRS recently made the data available as XML files. Form990.xlsm directly imports data in separate sheets for each institution. This paper demonstrates how to use this tool by analyzing a small sample of similar colleges. We compare Form 990 data with IPEDS and find substantial agreement, but important differences. Form 990 data offer researchers an alternative to IPEDS for higher education work and enable evaluation of hospitals, political associations, service organizations, and other nonprofits

FIM DA DESONERAÇÃO TRIBUTÁRIA DA CESTA BÁSICA E IMPACTOS NA RENDA DA POPULAÇÃO BRASILEIRA

Este estudo investiga os impactos distributivos do fim da desoneração da cesta básica, caso seja aprovada a Reforma Tributária com base na Proposta de Emenda à Constituição n° 45 – (PEC - 45), que promove alterações nos principais tributos sobre o consumo (IPI, PIS, COFINS, ICMS e ISS). As análises foram realizadas a partir dos micro dados da Pesquisa de Orçamentos Familiares (POF) 2017/2018. Os resultados indicam um aumento de arrecadação próximo de R$5,1 bilhões, que irão comprometer proporcionalmente mais a população com menos renda. No entanto, a maior parte do acréscimo na arrecadação seria sobretudo nos 50$ 3,4 bilhões a mais de tributos. Como a PEC – 45 prevê um mecanismo de devolução aos consumidores de baixa renda dos tributos pagos pelo fim da desoneração da cesta básica, o estudo demonstra que caso essa devolução seja feita integralmente aos mais pobres, a arrecadação dos R$5,1 bilhões seria pouco afetada. A devolução total desse aumento aos 30$ 788 milhões

Efecto de la dosificación de cal en la remoción de hierro y cobre del efluente de la empresa minera San Simón- La Libertad

En el presente trabajo de investigación se realiza la dosificación con cal para remover concentraciones de hierro y cobre del efluente de la empresa minera San Simón, ubicada en el caserío Tres Ríos, provincia Santiago de Chuco – La Libertad. El efluente se caracteriza por tener un pH ácido de un valor promedio de 3.51 y una concentración promedio de hierro y cobre de 61.935 y 19.415 ppm respectivamente. Las tres muestras tomadas del efluente minero fueron de 9 litros cada una, el tratamiento experimental se realizó a diferentes tiempos (30, 60 y 90 minutos) y a diferentes concentraciones de óxido de calcio (40, 80, y 120 g/L). Se empleó el espectrofotómetro de absorción atómica a la llama para determinar las concentraciones de hierro y cobre antes y después del tratamiento, además se usó el ph-metro para medir el pH de las nuestras. Según los resultados obtenidos, la cantidad de cal adecuada debe ser 80 gramos por litro de efluente en un tiempo de agitación de 90 minutos de tratamiento, porque se logra una buena remoción y se cumple con la normativa ambiental vigente de acuerdo al decreto supremo N° 010-2010-MINAM. Finalmente, en los resultados obtenidos se evidenciaron la influencia del tiempo de agitación y del pH en la remoción de los metales pesados antes mencionados. Dado que, a medida que el pH y el tiempo de agitación se incrementa, disminuye la concentración de hierro y cobre