News and Updates


The Importance of Studying Individual Trajectories, Even for Countries

May 31, 2018

The analysis of longitudinal data has quickly gained in importance across a variety of fields because it allows for the examination of questions about change over time. This is why all of our current workshops (Network Analysis, Latent Class/Mixture Modeling, Multilevel Modeling, Structural Equation Modeling, and Longitudinal Structural Equation Modeling) address the analysis of longitudinal…

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Statistical Adjustment and the Case of Marathon Records and Climate Change

November 9, 2017

There is often much confusion about what is meant by “statistical adjustment” when estimating and interpreting models that include more than one predictor variable. This issue commonly arises in the traditional multiple regression model, but is ubiquitous across nearly any class of multivariate models ranging from regression to factor analysis to complex structural equation models.…

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Using Nested Data to Enhance Causal Inference

May 30, 2017

There has been an ongoing controversy about whether a mother’s use of antidepressants during pregnancy results in elevated rates of autism in their children. Although much research has focused on this question, it has been limited by the omission of potential confounding variables and the study of just one child per mother. A recent study…

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Regression to the Mean in Everyday Life

May 12, 2017

Regression to the mean is an often misunderstood phenomena that routinely arises in both empirical research and in every day life. First described by Sir Francis Galton, regression to the mean is a process by which a measured observation that obtains an extreme value on one assessment will tend to obtain a less extreme value…

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The Importance of Age-Period-Cohort Effects

February 17, 2017

One of the most interesting and challenging aspects of longitudinal research is the need to disentangle age, period, and cohort effects when studying individual stability and change over time. Age effects reflect how many years an individual has been alive; period effects reflect the time-varying influences on the individual as they age; and cohort effects…

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How a Collection of Small Errors Led to Incorrect Projections in National Election Polls

December 18, 2016

Regardless of political affiliation, millions around the globe were surprised to awake November 9th to learn the Mr. Trump was the president-elect of the United States. Poll after poll leading up to the contest suggested that Secretary Clinton would prevail, albeit by a small margin. Even Saturday Night Live’s spoof of the final debate introduced…

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Intensive Longitudinal Data and Fitness Trackers

November 17, 2016

Nearly all of us carry a powerful computer throughout our waking hours in the form a smart phone. Remarkably, even the most basic iPhone has vastly more computational power than the entire set of computers that guided Apollo 11 to the moon. The ubiquity of smart phones has led to the easy (and potentially too…

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Psychometrics in Everyday Life

November 6, 2016

The term psychometrics is broadly defined as the theory and methods of mental measurement. The historical roots of psychometrics date back more than a century, the birth of which is sometimes marked by Spearman’s seminal 1904 paper titled General Intelligence, Objectively Determined and Measured in which factor analysis was first described as a formal statistical…

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The Human Desire to Categorize

July 4, 2016

Whether colors in the rainbow, notes in a musical scale, types of coffee, or country versus pop singers, there is a natural human desire to categorize objects and experiences. A story that recently appeared in the New York Times by Tom Vanderbilt presents a wonderful exploration of how we all find comfort in defining, seeking…

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Inferring Cause and Effect in Time Series

December 15, 2015

One of the greatest challenges in social science research is to validly identify cause-and-effect relations. A recent interactive graphic in the New York Times highlights a prospective, quasi-experimental approach to linking increased gun sales to specific social and political events.

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