Figure 4.
A line diagram plots productivity on the vertical axis and time on the horizontal axis. The productivity curve begins near the level marked 1, then declines after the vertical dashed line labelled T 1. The curve continues downward to a lowest point near the vertical dashed line labelled T 2, and then increases gradually until it approaches the level near 1 again close to the vertical dashed line labelled T R E. The section of the declining curve between T 1 and T 2 is labelled robustness with an arrow pointing to the slope of the curve. A small triangular marker appears near the declining section of the curve. Vertical dashed lines mark the time points T 1, T 2, and T R E.Robustness
Source: Authors’ own work