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Many college students drop STEM majors after struggling in gateway courses, in part because these courses place large demands on students9 time. In three online experiments with two different lessons (measures of central tendency and multiple regression), we identified a promising approach to increase the efficiency of STEM instruction. When we removed lectures and taught participants exclusively with practice and feedback, they learned at least 15% faster. However, our research also showed that this instructional strategy has the potential to undermine interest in course content for less-confident students, who may be discouraged when challenged to solve problems without upfront instruction and learn from their mistakes. If researchers and educators can develop engaging and efficacy-building activities that replace lectures, STEM courses could become better learning environments. 

What does it mean to be a better model? One conceptualization, indeed a common one in Educational Data Mining, is that a better model is the one that fits the data better, that is, higher prediction accuracy. However, oftentimes, models that maximize prediction accuracy do not provide meaningful parameter estimates. Here we argue that models that provide meaningful parameters are better models and, indeed, often also provide higher prediction accuracy. To illustrate our argument, we investigate the Performance Factors Analysis (PFA) model and the Additive Factors Model (AFM). PFA often has higher prediction accuracy than the AFM; however, PFA申fs parameter estimates are ambiguous and confounded. We propose more interpretable models (AFMh and PFAh) designed to address the confounded parameters and demonstrate PFA申fs confounding issues with synthetic data. The results from the experiment with 27 real-world dataset also support our claims and show that the more interpretable models can produce better predictions. 

Logistic Knowledge Tracing (LKT) is a framework for combining various predictive features into student models that are adaptive, interpretable, explainable, and accurate. While the name logistic knowledge tracing was coined for our R package that implements this methodology for making student models, logistic knowledge tracing originates with much older models such as Item Response Theory (IRT), the Additive Factors Model (AFM), and Perfor-mance Factors Analysis (PFA), which exemplify a type of model where student performance is represented by the sum of multiple components each with some sort of feature computed for the component. Features may range from the simple presence or ab-sence of the component to complex functions of the prior history of the component. The LKT package provides a simple interface to this methodology, allowing old models to be specified or new models to be created by mixing and matching components with features. We will provide concrete examples of how the LKT framework can provide interpretable results on real-world datasets while being highly accurate. 

Cognitive science of learning points to solutions for making use of existing study and instruction time more effectively and efficiently. However, solutions are not and cannot be one-size-fits-all. This paper outlines the danger of overreliance on specific strategies as one-size-fits-all recommendations and highlights instead the cognitive learning processes that facilitate meaningful and long-lasting learning. Three of the most commonly recommended strategies from cognitive science provide a starting point; understanding the underlying processes allows us to tailor these recommendations to implement at the right time, in the right way, for the right content, and for the right students. Recommendations regard teacher training, the funding and incentivizing of educational interventions, guidelines for the development of educational technologies, and policies that focus on using existing instructional time more wisely.