Start with the question.
Choose methods and tools around the scientific problem. Make the causal question, study timing, and data requirements explicit.
Study Design Studio ↗About Black Swan Causal Labs
Better evidence starts
with better questions.
We build software and methods that help researchers make their reasoning explicit—from a causal question to a study design and the evidence used to assess it.
Independent labLos Angeles, California
Why this lab exists
The decisions before
the analysis matter.
Which question are we asking? What assumptions does the answer depend on? Does the study design—and the available data—support that question?
These decisions run through real-world evidence work. Black Swan Causal Labs brings them into tools researchers can use, inspect, and discuss. Causal diagrams, study timelines, reporting checklists, and risk-of-bias assessments make different parts of that reasoning visible.
AI creates new ways to support this work. Scientific judgment gives it direction.
Explore the tools
The founder / The experience behind the work
Researcher. Builder. Educator.
John D.
Diaz-Decaro
Ph.D., M.S.
Founder & Principal, Black Swan Causal Labs
John brings more than a decade of experience generating regulatory-grade real-world evidence across global public health, vaccines, autoimmune disease, and oncology programs.
His work spans industry evidence generation, public health research, teaching, and the evolving role of AI in pharmacoepidemiology.
- Evidence generation
- Former RWE leader at Moderna and GlaxoSmithKline.
- Scientific community & policy
- Chair, Digital Technology & AI Special Interest Group, International Society for Pharmacoepidemiology. Editorial board member, Pharmacoepidemiology and Drug Safety (PDS), supporting the AI/ML section. Policy contributions to FDA, EMA, CIOMS, and ICH draft guidance on AI, real-world data, and real-world evidence.
- Teaching & public health
- Former lecturer in Epidemiology, Public Health, and Environmental Health at UCLA and CSUDH. Former Public Health Research Microbiologist at the Los Angeles County Department of Public Health.
How we approach the work
Make the reasoning inspectable.
Show the assumptions.
A result is only as useful as the reasoning behind it. Surface the relationships and choices that a researcher needs to examine.
DAG Studio ↗Keep judgment in the loop.
Use AI to assist drafting and review. Keep evidence, limitations, and the researcher’s responsibility visible throughout the process.
ROBINS-I assessment ↗Work with the lab
Bring a question worth working on.
Explore the tools, exchange ideas, or discuss a research collaboration.