Title: Estimation of Speed-Accuracy Response Models: Positive Scoring Rules for Easy Tests Authors: Peter van Rijn (1), Usama Ali (2) Affiliation: (1) ETS Global, (2) Educational Testing Service Abstract: We develop an estimation routine to estimate item response models that combine response accuracy and response time in a straightforward scoring rule. This was proposed by Maris and van der Maas (2012), who focused on a psychometric model for multiple choice items in which the scoring rule resulted in positive scores for fast correct responses and negative scores for fast incorrect responses. The resulting score is treated as a sufficient statistic, and leads to an exponential family model. We will focus on a scoring rule that results in positive scores only, and discuss model estimation using minorization techniques (see e.g., de Leeuw, 2006). The minorization is however different from that used in Maris and van der Maas (2012). Finally, we discuss a method for assessing item fit based on residual analysis following Haberman, Sinharay, and Chon (2013). The methods are illustrated with simulations and an application to real data from a relatively easy mathematics assessment. It is found that adding the response time can lead to a considerable improvement in measurement precision. References: Haberman, S., Sinharay, S., & Chon, K. (2013). Assessing item fit for unidimensional item response theory models using residuals from estimated item response functions. Psychometrika, 78, 417-440. de Leeuw, J. (2006). Some majorization techniques. Statistical Computing and Graphics Newsletter, 17, 3-7. Maris, G., & van der Maas, H. (2012). Speed-accuracy response models: Scoring rules based on response time and accuracy. Psychometrika, 77, 615-633.