OptionalnullThe value that means "no effect" -- 1 for a ratio measure, 0 for a difference.
Whether an interval crosses it is the result for that study, so the trace announces the crossing. There is deliberately no default: a ratio chart guessed at 0 would report every study as not crossing, since odds ratios are all positive, and that is a confident wrong answer given to every row. A layer that does not declare it gets the estimate, the interval and the weight, and no claim about significance.
Display configuration for a forest plot layer.