ATLAS Estimation: “specification :: negative control - invalid” error when adding negative controls

Hello,

I’m setting up an Estimation study in ATLAS and am running into an error when I try to include negative controls. The study saves fine without them, but as soon as I add the negative control option, I get:

specification :: negative control - invalid

When I look at the Evaluation Settings panel, I see options for event occurrence, descendants, and domain selection (screenshot below), but I don’t see anywhere to actually specify which negative control outcomes to use.

My questions are:

  • How are negative controls supposed to be specified in ATLAS? Should they be imported as a CSV of concept IDs, selected from concept sets, or defined as outcome cohorts?
  • Is there a particular ATLAS/WebAPI version where the UI for this is different?
  • Has anyone seen this exact “specification :: negative control - invalid” message, and if so, what resolved it?

Any guidance or examples would be greatly appreciated.

Thanks,
Justin