LMX theory addresses leadership as a process of interactions between leaders and followers. Early studies found leaders form different quality relationships ("in-groups" and "out-groups") with followers, with in-groups having high-quality exchanges like trust and influence. Later studies showed high-quality LMX leads to less turnover and better performance. Critics argue LMX can seem unfair and lacks standardized measures. Further research examined how perceptions of LMX quality can differ between leaders and followers.