I have two univariate time-series with seasonality and trend--dt1 and dt2. I believe that dt1 and dt2 are strongly correlated, both through a few statistical test (see below) and that in my field dt2 is a proxy for dt1.
Linear Regression Research
Ultimately I want to use dt1 off dt2.I don't actually need to forecast dt2 or make predictions about it, since it is a leading indicator and I actually can collect that data before dt1 is available.
Since I don't need to actually predict/forecast dt1 on it's own--I don't think (and I can be completely wrong) ARIMA or lagged/autoregressive studies--I am using dt2 to forecast it.
Is a Linear Regression the best starting point (even with dt1 having obvious season/trend time components)--should I be looking into a ARIMAX or another tool?