https://www.nature.com/articles/s44260-024-00014-y
Protocols are featured as a case study in this paper multiple times, with some interesting findings. Working my way through the paper today and I’ll drop my notes here 
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The three most interesting things I found in the paper were about protocol variance, types of antifragility, and correlates of antifragility in technical systems.
Page 4, Fig. 4: “…Low-variance protocols are optimal to maximize response for concavity; high-variance protocols for convexity.”
The examples given were cancer treatment and pest management. Consistent intervention can select for treatment resistant cells or pesticide resistant pests. Taking breaks (i.e. using a high-variance protocol) can help avoid that. A low-variance protocol is good for situations like improving aerobic fitness, where you can simply add volume of easy exercise (like walking), without big second-order risks
The authors cited a source that suggested there are six types of antifragility, three types for technical systems (intrinsic, inherited, induced) and three corresponding types for natural/biological systems (ecological, evolutionary, and interventional). Induced / interventional antifragility both have to do with control, so they seem like the most relevant to protocol science.
Last thing that stood out to me (emphases mine):
“The control-theoretic approach to induced antifragility focuses on the combination of timescale separation and redundant overcompensation with variable structure control. A controller guides the system to the antifragile region of its operational domain through a judicious choice of an external control or regulation signal. This can be accomplished by properly synthesizing a control law, which develops a redundant overcompensation capacity to handle uncertainty regarding the sensor and actuator failures by pushing the closed-loop system dynamics to prescribed dynamics.”
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