Analysis confirms what many on the Street were already thinking: biotech executives leaving ahead of late-stage clinical data often means the study will fail, according to one Citi analyst.

Citi’s Yigal Nochomovitz based that conclusion on 79 instances of positive and negative study results, finding that 70% of the time when an executive left ahead of data, it meant the study wasn’t successful.

Among examples Nochomovitz found was ImmunoGen Inc. Shares were trading over $5 before the drug developer’s chief financial officer stepped down in November. ImmunoGen’s stock cratered in March when a highly anticipated ovarian cancer study failed to stave off the return of patients’ cancers longer than chemotherapy.

Prothena Corp. followed a similar trajectory when the company announced in February 2018 that its chief medical officer would leave, ahead of a failed study that April.

Not every departure signals bad news. But Citi found 12 departures ahead of 39 negative data readouts compared with five out of 40 ahead of successful studies.

Citi’s theory may get a further test with Atara Biotherapeutics Inc.

The biotech’s co-founder and chief executive left his post in June. The Street is waiting on early-stage efficacy data in multiple sclerosis later this year, while late-stage data in transplant patients with a life-threatening complication is expected in 2020.