Hello, I am a new Stata learner and having some difficulty coding. Say if blood pH was recorded for patients on mechanical ventilation from day 1 to 14; the preface is that they will be eligible for a certain treatment if pH is greater than a certain number (eg. 7.2). How do I code on to Stata such that I can generate 2 outputs, 1) the day they met the criteria so from days 1 to 14, when did they become eligible for treatment given if pH>7.2 and 2)record of the pH from the day they became eligible.