David Allison

As a methodologist, I like challenges, job security, and it's fun.

I like figuring things out.

So it's, we can't randomize everything.

So how do we get causal inference?

We can't blind every aspect of diet.

And if we could, we'd be missing some of what we're trying to study because some of the effects of diet involve the effects of perceiving what you're eating.

Some of the effects of this drink I'm drinking is how it tastes.

And if you blind me to it, then you've taken away that potential effect.

There are issues of measurement.

How do you know what I really ate?

There are issues of adherence.

If you tell me to drink one of these every day, do I actually do it?

Do I drink one and only one as you've instructed?

There are issues of duration.

Could you get me to drink it now and measure something in me 15 minutes later?

Sure.

Could you get me to drink one every day for the next 20 years and measure stuff?

Difficult.

The issues of the model organism.

One thing is, we're going to talk about longevity a little bit.