Loops that Matter (LTM) provides a practical and comprehensive way to understand which feedback loops are driving model behavior at different points in time. LTM describes from which loops the observed change in behavior across all stocks in the model originate. In this paper we present a method to measure the magnitude of the change in behavior of all stocks in the model based on net flow values, relative to the magnitude of change taking place across an entire observation (simulation) period. We call this new metric the “system change”. We then demonstrate how our system change metric can be visualized using loop scores to highlight those loops that are predominantly responsible for the changes in behavior exhibited by the model. This helps analysts focus in on the feedback loops that are prime candidates for interventions to change the model behavior. © 2023 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.

中文翻译：

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使用单个指标来衡量系统行为的变化

Loops that Matter (LTM) 提供了一种实用且全面的方法来了解哪些反馈循环在不同时间点驱动模型行为。LTM 描述了模型中所有股票的观察到的行为变化源自哪个循环。在本文中，我们提出了一种方法，根据净流量值来衡量模型中所有股票的行为变化幅度，相对于整个观察（模拟）期间发生的变化幅度。我们将这个新指标称为“系统变化”。然后，我们演示如何使用循环分数来可视化我们的系统更改指标，以突出显示主要负责模型表现出的行为变化的那些循环。这有助于分析师专注于反馈循环，这些反馈循环是改变模型行为的干预措施的主要候选者。© 2023 作者。系统动力学评论由 John Wiley & Sons Ltd 代表系统动力学协会出版。