logical-relationship standard.Civil procedure. A test applied to determine whether a defendant’s counterclaim is compulsory, by examining whether both claims are based on the same operative facts or whether those facts activate additional rights, otherwise dormant, for the defendant. • One of the most important factors considered is whether hearing the claims together would promote judicial economy and efficiency. Fed. R. Civ. P. 13(a). [Cases: Federal Civil Procedure  776; Set-off and Counterclaim  60.C.J.S. Set-off and Counterclaim §§ 102–103.]

“[U]nder the fourth test — frequently referred to as the ‘logical relationship’ standard — the principal consideration in determining whether a counterclaim is compulsory rests on the efficiency or economy of trying the counterclaim in the same litigation as the main claim. As a result, the convenience of the court, rather than solely the counterclaim’s relationship to the facts or issues of the opposing claim, is controlling. The hallmark of this approach is flexibility. Although the fourth test has been criticized for being overly broad in scope and uncertain in application, it has by far the widest acceptance among the courts.” Jack H. Friedenthal et al., Civil Procedure § 6.7, at 352 (2d ed. 1993).
[Blacks Law 8th]