@subsubheading Description

This is a matched case-control study dating from before the availability of
conditional logistic regression.

@subsubheading Format

@table @code
@item education
Index of the record.
@item age
Age in years of case.
@item parity
Count.
@item induced
Number of prior induced abortions, grouped into “0”, “1”, or “2 or more”.
@item case_status
0 = control, 1 = case.
@item spontaneous
Number of prior spontaneous abortions, grouped into “0”, “1”, or “2 or more”.
@item stratum
Matched set number.
@item pooled_stratum
Stratum number.
@end table

@subsubheading Note

One case with two prior spontaneous abortions and two prior induced abortions is omitted.

@subsubheading Source

Trichopoulos et al (1976). @cite{Br. J. of Obst. and Gynaec.} 83, 645–650.

@subsubheading Examples

@example
@INCLUDE_DATASET_EXAMPLE_SCRIPT{infert_1.m}
@end example
