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Each time a learner in a self-paced online course seeks to answer an assessment question, it takes some time for the student to read the question and arrive at an answer to submit. If multiple attempts are allowed, and the first answer is incorrect, it takes some time to provide a second answer. Here we study the distribution of such "response times." We find that the log-normal statistical model for such times, previously suggested in the literature, holds for online courses. Users who, according to this model, tend to take longer on submits are more likely to complete the course, have a higher level of engagement, and achieve a higher grade. This finding can be the basis for designing interventions in online courses, such as MOOCs, which would encourage "fast" users to slow down.

We propose to change the default P-value threshold for statistical significance for claims of new discoveries from 0.05 to 0.005.

Dealing with the vast quantities of text that students generate in Massive Open Online Courses (MOOCs) and other large-scale online learning environments is a daunting challenge. Computational tools are needed to help instructional teams uncover themes and patterns as students write in forums, assignments, and surveys. This paper introduces to the learning analytics community the Structural Topic Model, an approach to language processing that can: 1) find syntactic patterns with semantic meaning in unstructured text, 2) identify variation in those patterns across covariates, and 3) uncover archetypal texts that exemplify the documents within a topical pattern. We show examples of computationally aided discovery and reading in three MOOC settings: mapping students' self-reported motivations, identifying themes in discussion forums, and uncovering patterns of feedback in course evaluations.

Massive open online courses (MOOCs) attract diverse student bodies, and course forums could potentially be an opportunity for students with different political beliefs to engage with one another. We test whether this engagement actually takes place in two politically-themed MOOCs, on education policy and American government. We collect measures of students' political ideology, and then observe student behavior in the course discussion boards. Contrary to the common expectation that online spaces often become echo chambers or ideological silos, we find that students in these two political courses hold diverse political beliefs, participate equitably in forum discussions, directly engage (through replies and upvotes) with students holding opposing beliefs, and converge on a shared language rather than talking past one another. Research that focuses on the civic mission of MOOCs helps ensure that open online learning engages the same breadth of purposes that higher education aspires to serve.

Political scientists designing experiments often face the question of how abstract or detailed their experimental stimuli should be. Typically, this question is framed in terms of trade‐offs relating to experimental control and generalizability: the more context introduced into studies, the less control, and the more difficulty generalizing the results. Yet, we have reason to question this trade‐off, and there is relatively little systematic evidence to rely on when calibrating the degree of abstraction in studies. We make two contributions. First, we provide a theoretical framework that identifies and considers the consequences of three dimensions of abstraction in experimental design: situational hypotheticality, actor identity, and contextual detail. Second, we replicate and extend three survey experiments, varying these levels of abstraction. We find no evidence that situational hypotheticality substantively changes results in any of our studies, but do find that increased contextual detail dampens treatment effects, and that the salience of actor identities moderates results in our endorsement experiment. [ABSTRACT FROM AUTHOR]

Traditionally in the social sciences, causal mediation analysis has been formulated, understood, and implemented within the framework of linear structural equation models. We argue and demonstrate that this is problematic for 3 reasons: the lack of a general definition of causal mediation effects independent of a particular statistical model, the inability to specify the key identification assumption, and the difficulty of extending the framework to nonlinear models. In this article, we propose an alternative approach that overcomes these limitations. Our approach is general because it offers the definition, identification, estimation, and sensitivity analysis of causal mediation effects without reference to any specific statistical model. Further, our approach explicitly links these 4 elements closely together within a single framework. As a result, the proposed framework can accommodate linear and nonlinear relationships, parametric and nonparametric models, continuous and discrete mediators, and various types of outcome variables. The general definition and identification result also allow us to develop sensitivity analysis in the context of commonly used models, which enables applied researchers to formally assess the robustness of their empirical conclusions to violations of the key assumption. We illustrate our approach by applying it to the Job Search Intervention Study. We also offer easy-to-use software that implements all our proposed methods. (Contains 7 figures, 7 tables and 14 footnotes.)