This matrix is a work in progress and is subject to revision and cross checking. But it provides comparative socio-economic and housing data for most of the study cities. The latest version was compiled and revised by Martha E. Castañeda Rivera and Dr. Edith Jimenez. Data were collected using the same basic generic survey instruments (see our Methodology section) and the full datafiles are available in Stata and SPSS (and sometimes in Excel) in the Merged & City Databases section. Where the datasets are compatible they are combined into a Master data matrix.