Our study examines the fit concept in the context of IS planning, a major research stream in the IS literature. Previous research reveals inconsistencies in the IS planning literature that may be due to a lack of congruence between the conceptual and statistical forms of fit employed within and between studies. We systematically examined the IS planning literature between 2000 and 2006 for congruence between the conceptual and statistical forms of fit. We found that 17% of studies lacked congruence and the most problematic area was with the bivariate representations of fit. We provide an empirical comparison of bivariate formulations and a decision tree to determine appropriate forms of fit.