Ventana software support forum

Hi,

I am a new user of Vensim. I would like to model Birth rate to be a variable type with time as we model in stella. Image file attached.

Similar to the below one:

Population(t) = Population(t - dt) + (Births) * dt
INIT Population = 1000
INFLOWS:
Births = Population*Birth_Rate
Birth_Rate = GRAPH(TIME)
(2016, 0.0802), (2017, 0.0849), (2019, 0.0894), (2020, 0.0939), (2022, 0.0986), (2023, 0.103), (2024, 0.108), (2026, 0.113), (2027, 0.118), (2029, 0.123), (2030, 0.127)

Can someone help me in modelling this in vensim. I am also confused on how to do this using lookup variable type.

It might be best if you visit the following page as they have a really good PLE tutorial. It will teach you all you need to do this.
http://www.public.asu.edu/~kirkwood/sysdyn/SDRes.htm

Thanks. I got to know how to do from one of your links. "Vensim PLE Quick Reference and Tutorial". Time has to be shadow variable.

https://vensim.com/lookups-in-vensim/ might be helpful.

Also: https://vensim.com/building-a-simple-vensim-model/