The statistical analysis of compositional data
The statistical analysis of compositional data
Computing LTS Regression for Large Data Sets
Data Mining and Knowledge Discovery
Non-linear PCA: a missing data approach
Bioinformatics
Principal component analysis for data containing outliers and missing elements
Computational Statistics & Data Analysis
A modified EM alr-algorithm for replacing rounded zeros in compositional data sets
Computers & Geosciences
Impact of non-normal random effects on inference by multiple imputation: A simulation assessment
Computational Statistics & Data Analysis
Editorial: Special issue on variable selection and robust procedures
Computational Statistics & Data Analysis
Iterative stepwise regression imputation using standard and robust methods
Computational Statistics & Data Analysis
Interpretation of multivariate outliers for compositional data
Computers & Geosciences
Exploring incomplete data using visualization techniques
Advances in Data Analysis and Classification
Model-based replacement of rounded zeros in compositional data: Classical and robust approaches
Computational Statistics & Data Analysis
Is compositional data analysis a way to see beyond the illusion?
Computers & Geosciences
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New imputation algorithms for estimating missing values in compositional data are introduced. A first proposal uses the k-nearest neighbor procedure based on the Aitchison distance, a distance measure especially designed for compositional data. It is important to adjust the estimated missing values to the overall size of the compositional parts of the neighbors. As a second proposal an iterative model-based imputation technique is introduced which initially starts from the result of the proposed k-nearest neighbor procedure. The method is based on iterative regressions, thereby accounting for the whole multivariate data information. The regressions have to be performed in a transformed space, and depending on the data quality classical or robust regression techniques can be employed. The proposed methods are tested on a real and on simulated data sets. The results show that the proposed methods outperform standard imputation methods. In the presence of outliers, the model-based method with robust regressions is preferable.