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Here - Tilburg University

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Author and presenter<br />

Ark van der, Andries; <strong>Tilburg</strong> School of Social and Behavioral Sciences<br />

Title<br />

Categorical Marginal Models for Large Sparse Contingency Tables<br />

Abstract<br />

Categorical marginal models (CMMs) are flexible tools to model location,<br />

spread, and association in categorical data that have some dependence<br />

structure.The categorical data are collected in a contingency table; location,<br />

spread, or association are modelled by restricting certain marginals of the<br />

contingency table. If contingency tables are large, maximum likelihood<br />

estimation of the CMMs is no longer feasible due to computer memory problems.<br />

We propose a maximum empirical likelihood estimation (MEL) procedure for<br />

estimating CMMs for large contingency tables, and discuss three related<br />

problems:The problem of finding the correct design matrices and the so-called<br />

empty set problem can be solved satisfactorily, the problem of obtaining good<br />

starting values remains unsolved. A simulation study shows that for small data<br />

contingency tables ML and MEL yield comparable estimates. For large tables,<br />

when ML does not work, MEL has a good sensitivity and specificity if good<br />

starting values are available.

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