The rule change for segment reporting in 1998 has arguably made segment reporting more relevant through the adoption of the management approach. Meanwhile, the management approach has resulted in a decrease in the comparability of segment income. We introduce firm-specific measures of changes in relevance and comparability due to the rule change. Our treatment firms experienced an increase in the relevance of segment reporting but a large decrease in the comparability of segment income; our benchmark firms barely experienced any changes in relevance and comparability. We examine earnings forecasts before vs. after the rule change issued by financial analysts—a major user group of segment reporting. Relative to benchmark firms, treatment firms’ analyst forecast error reductions around the segment disclosure event are not significantly different after the rule change than before the rule change, but treatment firms’ forecast dispersion reductions around the segment disclosure event are significantly larger after the rule change than before the rule change. These results suggest that despite the decrease in comparability, the new segment reporting rule has increased the decision usefulness of segment information by decreasing disagreement among analysts.

1998年分部报告的规则变更可以说是通过采用管理方法使分部报告更加相关。同时，管理方法导致分部收入的可比性下降。由于规则的变化，我们介绍了针对公司的相关性和可比性变化的度量。我们的治疗公司的分部报告相关性有所提高，但分部收入的可比性却大大下降。我们的基准公司在相关性和可比性方面几乎没有任何变化。我们检查了财务分析师发布的规则变更之前和之后的收益预测。财务分析师是细分报告的主要用户群体。相对于基准公司，规则变更后，处理公司对部门披露事件周围的分析师预测误差减少与规则更改之前没有显着差异，但是规则更改后，处理公司对部门披露事件周围的预测分散误差减少比规则更改之前显着更大。这些结果表明，尽管可比性有所下降，但新的细分市场报告规则通过减少分析师之间的分歧，提高了细分市场信息的决策有用性。