Austin Messner's paper proposing component control for TMS trials is out in @brainstimj . brainstimjrnl.com/article/S1… The problem it addresses is one most of us in the TMS field have run into. A modern accelerated protocol varies several things at once: how the target is chosen, pulses per session, sessions per day, total treatment days. When the protocol works, the trial has told us the package works. It has not told us which component carries the effect, and often the design could not have told us even in principle. We propose two things. A Component Map: a figure accompanying each multicomponent trial that shows which components were manipulated and which were experimentally isolated versus confounded. The Component Control Index (CCI): the ratio of controlled to total manipulated components, ranging from 0 to 1. A component counts as controlled when at least one contrast in the design varies that component alone. What CCI is not is as important as what it is. It is a descriptive reporting tool, not a quality metric and not a ranking. A proof-of-concept trial of a novel bundled protocol will have a low CCI, and that is appropriate; establishing that something works comes first. Decomposing it is the complementary next step. The index simply makes the inferential boundary of each design explicit. What CCI is not is as important as what it is. It is a descriptive reporting tool, not a quality metric and not a ranking. A proof-of-concept trial of a novel bundled protocol will have a low CCI, and that is appropriate; establishing that something works comes first. Decomposing it is the complementary next step. The index simply makes each design's inferential boundary explicit. Precedent shows why this matters. Psychotherapy research spent years dismantling treatment packages after they were already in widespread use, and found that behavioral activation alone accounted for much of CBT's effect in depression. That finding produced more parsimonious and more scalable treatments - but it arrived late. Neuromodulation is at the point in its development where that work can be done early rather than retrospectively. Proud of Austin Messner, who led this work! Wouldn't have been possible without @tgroveradams and Elizabeth Arnold.