What exactly is causal inference? How do you use it in your job?

I have a background in medical research. I'm getting confused with data science terminology. Is causal inference the same in medical research and data science? So you do eg an RCT to determine treatment effect then Treatment effect = (Outcome under E) minus (Outcome under C)?

Or in data science I guess it's A/B testing and measuring the effect when people are randomised to A or B. How do you use it?

When I first heard of it I thought …

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