WTSD (Went To ShowDown) is the percentage of hands in which, after seeing the flop, you go all the way and show your cards.
How it's calculated
The healthy ranges on the side are guidelines for NL Hold'em cash games with 100 bb stacks, the same ones Flopmortem compares your game against. Use them to spot big deviations, not as an exact target: they depend on the table, your opponents and your style.
How to read your WTSD
A high WTSD usually means you call too many rivers with weak hands: the classic calling station. A low one means you fold a lot on the turn and river and let opponents bluff you.
Read it alongside W$SD: reaching showdown a lot and winning little there is the clearest sign that you call too much.
If your WTSD is out of range
Too low
You rarely reach showdown: you fold a lot on the turn/river or don't call enough.
Too high
You reach showdown too often: you're probably calling rivers with weak hands. Fold more on the river.
How many hands you need to trust it
Flopmortem doesn't flag your WTSD as a leak until it has at least 60 opportunities. From there it calculates it with its 95% confidence interval: if the whole interval falls outside the healthy range, the leak is confirmed; if only the measured value is outside, it's a trend. The guide how many hands you need to trust your stats explains it.