In this article, we review four software packages for implementing propensity score analysis in R: "Matching, MatchIt, PSAgraphics," and "twang." After briefly discussing essential elements for propensity score analysis, we apply each package to a data set from the Early Childhood Longitudinal Study in order to estimate the…

The focus of the present study was on the mediation and moderation effects of reading processes as evidenced from eye movements on the relation between cognitive and linguistic student characteristics (word decoding, vocabulary, comprehension skill, short-term memory, working memory, and nonverbal intelligence) and text comprehension. Forty 4th…

Students explored variation and expectation in a probability activity at the end of the first year of a 3-year longitudinal study across grades 4-6. The activity involved experiments in tossing coins both manually and with simulation using the graphing software, "TinkerPlots." Initial responses indicated that the students were aware of…