ABSTRACTAltough the dual resource‐constrained (DRC) system has been studied, the decision rule used to determine when workers are eligible for transfer largely has been ignored. Some earlier studies examined the impact of this rule [5] [12][15] but did not include labor‐transfer times in their models. Gunther [6]incorporated labour‐transfer times into his model, but the model involved only one worker and two machines. No previous study has examined decision rules that initiate labor transfers based on labor needs (“pull” rules). Labor transfers always have been initiated based on lack of need (“push” rules).This study examines three “pull” variations of the “When” labor‐assignment decision rule. It compares their performances to the performances of two “push” rules and a comparable machine‐limited system. A nonparametric statistical test, Jonckheere'sSstatistic, is used to test for significance of the rankings of the rules: a robust parametric multiple‐comparison statistical test, Tukey'sBstatistic, is used to test the differences.One “pull” and one “push” decision rule provide similar performances and top the rankings consistently. Decision rules for determining when labor should be transferred from one work area to another are valuable aids for managers. This especially is true for the ever‐increasing number of managers operating in organizations that recognize the benefits of a cross‐trained work force. Recently there has been much interest in cross‐training workers, perhaps because one of the mechanisms used in just‐in‐time systems to handle unbalanced work loads is to have cross‐trained workers who can be shifted as demand dictates [8]. If management is to take full advantage of a cross‐trained