1: Adding the sizing photos is what cut the product-return rate. · 2: Before the photos the rate eased only a point a quarter, far below the five-point post-photo drop.
Falkner and Garza agree on the numbers in the report but split on what they mean. The columns ask you to pin the real point of disagreement and then find the one fact that would resolve it.
The disagreement. Both leads accept that the recorded return rate fell five points, and both accept that the rate had been sliding for months before the photos; Garza says so and Falkner does not dispute it. What they actually divide on is whether the photos cut returns, or whether the latest drop is just the earlier slide continuing on its own. Falkner says the photos did it; Garza doubts it. That is the claim they disagree about.
The arbiter. The disagreement hangs on whether the drop is the photos or the pre-existing slide. Both sides agree the rate had been sliding, so the question is whether the latest drop is just more of that slide or something bigger. The fact that would settle it for Falkner compares the pace: before the photos the rate had been easing only about a point a quarter, but right after them it dropped five points in a single quarter. If the post-photo fall is far steeper than the gentle slide that preceded it, the slide alone cannot account for it, and the photos are what changed. That controls for the very thing Garza blamed, the prior trend, by measuring how fast it had been moving. That is the finding that vindicates Falkner.
Watch the two pulls. The recorded-fall statement, that returns went from 14 percent to 9 percent, looks like the disagreement, but it is the shared starting point: neither lead disputes the number, so it cannot be what they argue over. And the long-slide statement is the basis of Garza's doubt, also accepted by both, so it too is common ground rather than the disagreement. Picking either as the disputed claim mistakes agreed ground for the dispute. For the finding that settles it, neither remaining fact resolves anything: that the photos were costly to produce, or that customers found the listings more helpful, says nothing about whether the photos, rather than the earlier slide, produced the drop. Notice too that the helpful-ratings fact leans Falkner's way in mood but does not separate the photos from the trend.
The discipline: the disagreement in a dialogue is the claim the speakers take opposite positions on, not the data they share, and the finding that settles it is the one that controls for the very thing the doubter blamed, here by measuring the pace of the slide just before the change.
Disagreement: whether the photos cut returns. Settles it for Falkner: the pre-photo slide was far gentler than the drop that followed.