Hi,

I am trying to analyze my 16S data using DESeq2, and I would like some advice on the correct formula I should use.

I have before/after data for two different treatments; also, I have 2 age classes. This is a sample of the table:

```
Patient Time Treatment AgeClass
p1 Before A C
p1 After A C
p2 Before A M
p2 After A M
p3 Before B C
p3 After B C
p4 Before B M
p4 After B M
```

As you can see, Treatment has two levels (A and B). I want to look at the effect of the two treatments, but also taking into account the age class of the patient. I was wondering if the following formula is correct:

```
~AgeClass + Treatment + Treatment:Patient + Treatment:Time
```

Should I make any change to the formula?

Thank you for your kind attention, Max

Thank you for the kind answer, and for the link to the paper, I appreciate it. I will read it and review my pipeline accordingly. I am sorry if my question has been asked repeatedly, I read a few topics and still I was not sure about my code.

Regarding the variables, for what I understand then, it should be either

or

but never "AgeClass" and "Patient" together.

Thanks again for taking the time to answering me.

Best,

Max