Survival analysis: First year the earlier 1 and Last year the later 1

[Yasutake Homma]

Hello, pls help know the commands how to do below.

【Background】
I have corporate panel data set containing of Corporate Code, Year, and various ratios.

【Survival】
I want to do survival that the first year should be a ratio over 1 in the earlier year and the last year should be the ratio over 1 in the later year.
For example, I have PPE/Asset ratio. I replaced the ratio as 1 if PPE/Asset >1. I want to analyze the cycle of big PPE expenses.

However, I have no idea how to input PPE/Asset == 1 in the earlier year and regard it as first year and PPE/Asset == 1 in the later year and regard it as last year.

If you could tell me how, it would be highly appreciated.

[David Benson]

It's not quite clear to me what you are asking for -- could you come back and post an example of your data (and what you would like it to look like)? Use Stata's dataex command to share a sample of your data. If you need help using dataex, there is a tutorial video here. (I made the video too long--feel free to watch at 2x speed, and you probably only need the first 6 minutes).