We show that there is no formal statistical testing method to support combining categories in a standard ordered regression model. We discuss practical implications of this result.

Additional Metadata
Keywords number of categories, ordered regression model
Persistent URL dx.doi.org/10.1111/j.1467-9574.2009.00432.x, hdl.handle.net/1765/18569
Series Econometric Institute Reprint Series
Journal Statistica Neerlandica
Franses, Ph.H.B.F, & Cramer, J.S. (2010). On the number of categories in an ordered regression model. Statistica Neerlandica, 64(1), 125–128. doi:10.1111/j.1467-9574.2009.00432.x