A curvilinear assessment of innovation in Six Sigma project teams: the influence of psychological safety and intrinsic motivation

Purpose To investigate the factors affecting innovation in Six Sigma improvement teams. Based on Activation Theory, this study explores the possibility of an inverted U-shaped association between psychological safety and innovation and examines how intrinsic motivation moderates this relationship. Design/methodology/approach Moderated regression analysis is carried out to test the curvilinear relationship, using data collected from 324 members of 102 Six Sigma improvement teams from two European manufacturing firms. Findings The findings demonstrate that the beneficial effect of psychological safety reaches an inflection point, after which its relations with innovation cease to be linear and positive; this gives the relationship a curvilinear pattern (inverted U-shaped). Further, intrinsic motivation has a supportive effect in enhancing the beneficial impact of psychological safety on innovation, and in shifting the inflection points to a higher level; this demonstrates their synergetic influence on innovation. Originality/value The impact of psychological safety on innovation is examined from the new perspective of a curvilinear relationship. This is one of the first studies to investigate the combined effects of individual (intrinsic motivation) and team-level antecedents (psychological safety) on innovation in Six Sigma teams. The study provides insights into how Six Sigma enhances innovation and offers some valid inputs to the current academic debate on this topic.