in the declination range $-40^\circ \leq \delta \leq -2.5 ^\circ$ and $b \leq -40^\circ$ (da Costa et al.  1994). Both SSRS2 and CfA2 are magnitude-limited to $m_{B_{0}} \leq 15.5$. SSRS2 is derived from plate scans. CfA2 is based on the Zwicky catalog. We use only the $cz$ range $300\ {\rm km\ s}^{-1}$ to $15,000\ {\rm km\ s}^{-1}$; the full sample we examine includes 14,011 galaxies.

The coordinate uncertainties in the redshift catalog are about one arcminute. We test the possible effects of the uncertainties on the very dense RSCG’s. They do not affect our compact group catalog.

Compact Group Selection in Redshift Space
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We develop an algorithm for identifying compact systems from a complete redshift survey. Our criteria mimic the ones established by Hickson. Application of our procedure to a [*distance limited*]{} redshift catalog would yield a set of systems with properties independent of distance. To obtain the largest possible sample of systems, we analyze a [*magnitude limited*]{} redshift survey. This limitation introduces some biases as a function of distance, but they are less severe than those introduced by selection on the sky. Because we start with a complete survey we can account for these biases.

The objective algorithm 