Publications by Rense Nieuwenhuis
Presenting Weighted Effect Coding
Weighted effect coding is a variant of dummy coding to include categorical variables in regression analyses, in which the estimate for each category represents the deviation of that category from the sample mean. The ‘wec’ package for R provides tools to use weighted effect coding. Manfred te Grotenhuis is currently visiting the Swedish Inst...
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New version of WEC: focus on interactions
We have uploaded a new version of WEC, an R package to apply ‘weighted effect coding’ to your dummy variables. With weighted effect coding, your dummy variables represent the deviation of their respective category from the sample mean, rather than the deviation from a reference category. Particularly with observational data, which are often u...
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Exact p-values for pairwise comparison of Friedman rank sums
BMC Bioinformatics has published a paper by colleagues of mine, about calculating exact p-values for pairwise comparison of Friedman rank sums. The paper provides fast and easy-to-use R code, making it an interesting read for anyone conducting the Friedman test. Fancy full text is available at http://rdcu.be/oOf9 Exact p-values for pairwise compa...
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When Size Matters: Weighted Effect Coding
Categorical variables in regression models are often included by dummy variables. In R, this is done with factor variables with treatment coding. Typically, the difference and significance of each category are tested against a preselected reference category. We present a useful alternative. If all categories have (roughly) the same number of obs...
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A novel method for modelling interaction between categorical variables
We have been developing weighted effect coding in an ongoing series of publications (hint: a publication in the R Journal will follow). To include nominal and ordinal variables as predictors in regression models, their categories first have to be transformed into so-called ‘dummy variables’. There are many transformations available, and popul...
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Weighted Effect Coding: New publication in the R Journal
Weighted effect coding is a technique for dummy coding that can have attractive properties, particularly when analysing observational data. In a new publication in the R Journal we explain the rationale of weighted effect coding, introduce the ‘wec’ package, and provide examples that include interactions. The attractive property of applying w...
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In Memoriam: Manfred te Grotenhuis
Manfred te Grotenhuis passed away. He was a respected sociologist, statistician, and teacher. I’ll leave it to others to comment on these achievements. To me, he was my teacher and mentor in statistics, and a dear colleague. Textbooks and other teachers have a lot to say about the theory of statistics, but it was Manfred who taught me the joy a...
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