In the speeded word fragment completion task, participants have to complete fragments such as tom_to as quickly and accurately as possible. Previous work has shown that this paradigm can successfully capture subtle priming effects (Heyman, De Deyne, Hutchison, & Storms Behavior Research Methods, 47, 580-606, 2015). In addition, it has several advantages over the widely used lexical decision task. That is, the speeded word fragment completion task is more efficient, more engaging, and easier. Given its potential, we conducted a study to gather speeded word fragment completion norms. The goal of this megastudy was twofold. On the one hand, it provides a rich database of over 8,000 stimuli, which can, for instance, be used in future research to equate stimuli on baseline response times. On the other hand, the aim was to gain insight into the underlying processes of the speeded word fragment completion task. To this end, item-level regression and mixed-effects analyses were performed on the response latencies using 23 predictor variables. Since all items were selected from the Dutch Lexicon Project (Keuleers, Diependaele, & Brysbaert Frontiers in Psychology, 1, 174, 2010), we ran the same analyses on lexical decision latencies to compare the two tasks. Overall, the results revealed many similarities, but also some remarkable differences, which are discussed. We propose that both tasks are complementary when examining visual word recognition. The article ends with a discussion of potential process models of the speeded word fragment completion task.Keywords Speeded word fragment completion task . Lexical decision task . Visual word recognitionIn the last decade, the field of visual word recognition has seen a surge in so-called megastudies (see Balota, Yap, Hutchison, & Cortese, 2012, for an overview). Generally speaking, a typical megastudy comprises several thousand items for which lexical decision, naming, and/or word identification responses are collected. The rationale behind megastudies is that they complement (traditional) factorial studies in which stimuli are selected on the basis of specific lexical or semantic characteristics. That is, factorial studies require one to experimentally control for a number of variables that could potentially obscure the effect(s) of interest. Megastudies, on the other hand, aim to gather data for as many stimuli as possible, without many constraints. The idea is that one can then statistically control for confounding variables by conducting a multiple regression analysis. In addition, continuous variables such as word frequency need not be divided into distinct categories (i.e., high-frequency vs. low-frequency words). This is a critical advantage of the megastudy approach, because artificially dichotomizing continuous variables has been shown to reduce power and increase the probability of Type I errors (Maxwell & Delaney, 1993).In the present study we sought to build on this work, and we describe a megastudy involving the speeded word Electronic supplementary ma...